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This study delineates biobased foods. Curcumin (CRU) delivery modules were studied using pectin gel, Sesame oil (SO), and Kokum butter (KB) oleogel (OG). SB1, the control, has 10% OG. The pectin gel between 10 and 50% oleogel were emulsified by 2.5% tween 80. Surface, physical, chemical, and physiochemical properties of prepared bigels were examined. Microscopic studies show biphasic feature. With OG content, FTIR shows hydrogen bonding increasing and decreasing. XRD confirmed gel amorphousness. Stress relaxation indicated 10% control bigel had considerably less strength. Bigel impedance factors increased considerably with OG content, according to impedance profiles. The moisture study found that replacing hydro phase with OG phase in formulations reduced moisture content from 10 to 50%. Less CRU released from 20 to 50% bigel matrices than 10% during in vitro studies. Acidic pH hindered polymer relaxation, altering release behaviour. Overall, the bigels were studied and shown to regulate oral CRU administration. [ABSTRACT FROM AUTHOR]

Herpes simplex virus infections are caused by two types (1 and 2) of the virus, being endemic worldwide and a frequent public health concern. For treatment, the drug of first choice is acyclovir (ACV), which acts by inhibiting viral DNA polymerase. However, its topical use in the form of ointments requires frequent application to achieve the desired efficacy, as it has low permeation. In this context, the use of biomaterials such chitosan (CS) as a carrier in the controlled release of drugs is an interesting alternative in health area. In the present work, CS-based membranes, microcapsules, and membrane/microcapsules were produced and characterized for encapsulation and release of the ACV. The membranes were produced using the casting technique, and the microcapsules were obtained through ionotropic gelation. The microstructures were characterized by infrared spectroscopy (FTIR-ATR), X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, mass loss and gain through water absorption tests, mechanical analysis, and release tests. Membranes with 23–33 ± 3 μm of thickness and microcapsules with ~ 1 mm of diameter were produced. FTIR spectra shows the typical vibrational regions related to the formed materials chemical groups. The found modulus of elasticity was 2.2 × 103, 1.5 × 103 and 1.1 × 103 MPa for CS, CS/glycerol 30% and CS/glycerol 30%/ACV membranes, respectively, suggesting higher rigidity for pure CS and least rigidity for ACV-containing membranes. TGA results show that all membranes are thermally stable up to 200ºC. The microcapsules and membrane/microcapsules systems showed better stability in drug encapsulation. Regarding to release assay, all microstructures demonstrate total ACV release, being calculated 101.5, 93.8, and 107.2% of concentration released for membrane, microcapsules, and membrane/capsules systems, respectively. The membrane/microcapsules modulated the release in 1 h and 20 min, with peak concentration at 2 h, while membrane and capsule systems had the entire drug released after 15/20 min. [ABSTRACT FROM AUTHOR]

[Display omitted] Chronic wounds affect millions of people annually and have emotional and financial implications in addition to health issues. The current treatment for chronic wounds involves the repeated use of bandages and drugs such as antibiotics over an extended period. A cost-effective and convenient solution for wound healing is the development of drug-incorporated bandages. This study aimed to develop a biocompatible bandage made of drug-incorporated poly (lactic-co-glycolic acid) (PLGA) microparticles (MPs) and eggshell membrane (ESM) for cornea wound healing. ESM has desirable properties for wound healing and can be isolated from eggshells using acetic acid or ethylenediaminetetraacetic acid (EDTA) protocols. Fluorescein isothiocyanate-labelled Bovine Serum Albumin (FITC-BSA) was used as a model drug, and the PLGA MPs were fabricated using a solvent extraction method. The MPs were successfully attached to the fibrous layer of the ESM using NaOH. The surface features of the ESM samples containing MPs were studied using a field emission scanning electron microscope (FESEM) and compared with blank ESM images. The findings indicated that the MPs were attached to the ESM fibres and had similar shapes and sizes as the control MPs. The fibre diameters of the MPs samples were assessed using Fiji-ImageJ software, and no significant changes were observed compared to the blank ESM. The surface roughness, Ra values, of the MPs incorporated ESM samples were evaluated and compared to the blank ESM, and no significant changes were found. Fourier transform infrared (FTIR) spectroscopy was used to analyse the chemical Composition of the bandage, and the spectra showed that the FBM were effectively incorporated into the ESM. The FTIR spectra identified the major peaks of the natural ESM and the PLGA polymer in the bandage. The bandage was transparent but had a reduced visibility in the waterproof test card method. The bandage achieved sustained drug release up to 10 days and was found to be biocompatible and non-toxic in a chorioallantoic membrane (CAM) assay. Overall, the drug-incorporated PLGA MPs-ESM bandage has great potential for treating chronic wounds. [ABSTRACT FROM AUTHOR]

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA was studied at a diverse temperature revealing different interaction modes; AuNRs@PEG may interact via groove-binding and AuNRs@PEG@NAP may intercalate to DNA-bases. The cleavage activity of the gold nanoparticles for supercoiled circular pBR322 plasmid DNA was studied by gel electrophoresis while their affinity for human and bovine serum albumins was also evaluated. Drug-release studies revealed a pH-sensitive behavior with a release up to a maximum of 24% and 33% NAP within the first 180 min at pH = 4.2 and 6.8, respectively. The cytotoxicity of AuNRs@PEG and AuNRs@PEG@NAP was evaluated against MCF-7 and MDA-MB-231 breast cancer cell lines. The development of AuNRs as an efficient non-steroidal anti-inflammatory drugs (NSAIDs) delivery system for chemotherapy is still in its infancy. The present work can shed light and inspire other research groups to work in this direction. [ABSTRACT FROM AUTHOR]

Biomaterial coatings and films can prevent premature failure and enhance the performance of chronically implanted medical devices. However, current hydrophilic polymer coatings and films have significant drawbacks, including swelling and delamination. To address these issues, hydroxyethyl cellulose is modified with thioether groups to generate an oxidation-responsive polymer, HEC MTP . HEC MTP readily dissolves in green solvents and can be fabricated as coatings or films with tunable thicknesses. HEC MTP coatings effectively scavenge hydrogen peroxide, resulting in the conversion of thioether groups to sulfoxide groups on the polymer chain. Oxidation-driven, hydrophobic-to-hydrophilic transitions that are isolated to the surface of HEC MTP coatings under physiologically relevant conditions increase wettability, decrease stiffness, and reduce protein adsorption to generate a non-fouling interface with minimal coating delamination or swelling. HEC MTP can be used in diverse optical applications and permits oxidation-responsive, controlled drug release. HEC MTP films are non-resorbable in vivo and evoke minimal foreign body responses. These results highlight the versatility of HEC MTP and support its incorporation into chronically implanted medical devices., (© 2024 Wiley‐VCH GmbH.)

In this study, gentamicin loaded collagen I/hyaluronic acid multilayers modified titanium coating (TC-AA(C/H)6-G) was fabricated via a layer-by-layer (LBL) covalent immobilization method. The drug releasing properties of collagen I/Hyaluronic acid (Col-I/HA) multilayers and the effect of loaded gentamicin on the antibacterial properties and cytocompatibility of modified TC were investigated. The gentamicin release assay indicated that the Col-I/HA multilayers modified TC exhibited agreeable drug-loading amount (537.22 ± 29.66 µg of gentamicin) and controlled-release performance (240 h of sustained release time). TC-AA(C/H)6-G revealed satisfactory antibacterial activity and inhibited the colonization and biofilm formation of S. aureus. Fortunately, the functions of hMSCs on TC-AA(C/H)6-G did not affected by the loaded gentamicin, and TC-AA(C/H)6-G could improve the adhesion, proliferation and osteogenic differentiation of cells, as well as TC-AA(C/H)6. In vivo animal study indicated that TC-AA(C/H)6-G could effectively control intramedullary cavity infection caused by S. aureus and prevent bone destruction.

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA was studied at a diverse temperature revealing different interaction modes; AuNRs@PEG may interact via groove-binding and AuNRs@PEG@NAP may intercalate to DNA-bases. The cleavage activity of the gold nanoparticles for supercoiled circular pBR322 plasmid DNA was studied by gel electrophoresis while their affinity for human and bovine serum albumins was also evaluated. Drug-release studies revealed a pH-sensitive behavior with a release up to a maximum of 24% and 33% NAP within the first 180 min at pH = 4.2 and 6.8, respectively. The cytotoxicity of AuNRs@PEG and AuNRs@PEG@NAP was evaluated against MCF-7 and MDA-MB-231 breast cancer cell lines. The development of AuNRs as an efficient non-steroidal anti-inflammatory drugs (NSAIDs) delivery system for chemotherapy is still in its infancy. The present work can shed light and inspire other research groups to work in this direction.

Zhou X, Tao H, Shi KH. Drug Des Devel Ther. 2018;12:1–8. The Editor and Publisher of Drug Design, Development and Therapy wish to retract the published article. Concerns were raised regarding the alleged duplication of images in Figure 5 with the same images from other unrelated articles. Specifically, Figure 5B, Liver appears to have been duplicated with the same image from Figure 4Bb from Li & Gong, 2016 (https://doi.org/10.2147/DDDT.S113670). Figure 5C, Liver appears to have been duplicated with the same image from Figure 4Bc from Li & Gong, 2016 (https://doi.org/10.2147/DDDT.S113670). Figure 5B, Spleen appears to have been duplicated with the same image from Figure 7A, Liver from Li & Wang, 2017 (https://doi.org/10.2147/IJN.S136378). Figure 5C, Spleen appears to have been duplicated with the same image from Figure 7B, Liver from Li & Wang, 2017 (https://doi.org/10.2147/IJN.S136378). The authors did not respond to our queries and no explanation for the alleged image duplication was provided. The Editor requested to retract the article and the authors were notified of this. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.

In this work, a novel free AgNPs composite, St-A-E/M, and nanocomposite beads, St-A-E/M-Ag, as a novel drug carrier were successfully prepared and used as controlled-release drug delivery systems for methyl prednisolone as a model drug. The structure of the resulted materials was identified using UV–Vis, SEM, EDX, XRD, FTIR, TEM, DLS, AFM and TGA/DTG spectroscopic techniques. The TEM and DLS results demonstrated that the incorporated AgNPs in the polymer matrix were spherical with diameters ranging from 50 to 111 nm. The influence of contact time, temperature, content of initial pH and Ag nanoparticles on the load and release behaviors of drug model was investigated under static conditions. The results indicated that the % release of drug model from the nanocomposite in different amounts of AgNPs was rather higher in comparison with the corresponding free-NPs composite. On the other hand, the results showed that the % release of drug increased by the increase in AgNPs content until 3.3% (V/V) in the polymer matrix, whereas that released beyond it was decreased. The maximum of release was also found within 9 h and at pH 7.4 for the nanocomposite. Furthermore, different release kinetic was employed for the description of the release process. Also, the nanocomposite exhibited higher antibacterial activity compared to the corresponding free-NPs composite. [ABSTRACT FROM AUTHOR]

Xiao Zhou, Hui Tao, Kai-Hu Shi Department of Cardiothoracic Surgery, The Second Hospital of Anhui Medical University, Hefei, People’s Republic of China Abstract: The aim of this study was to develop PEGylation liposomes formulations of erlotinib and evaluate their characteristics, stability, and release characteristics. The average particle sizes and entrapment efficiency of PEGylation erlotinib liposomes are 102.4±3.1 nm and 85.3%±1.8%, respectively. Transmission electron microscopy images showed that the liposomes dispersed well with a uniform shape and no changes during the storage. The in vitro drug-release kinetic model of erlotinib release from the PEGylation liposomes in phosphate-buffered saline fit well with the Higuchi equation. In vitro anticancer activity assay showed that the blank liposomes had lower cellular cytotoxicity and that the cellular cytotoxicity of erlotinib liposomes increased significantly under the same incubation condition, which should contribute to the increase in intracellular drug concentration by the transportation of liposomes. The two liposomes of erlotinib (with and without PEGylation) exhibited similar cellular cytotoxicity with no significantly different concentrations. Pharmacokinetic results indicated that erlotinib-loaded PEGylation liposomes can significantly change the pharmacokinetic behavior of drugs and improve the drug bioavailability by nearly 2 times compared to ordinary liposomes. No sign of damages such as the appearance of epithelial necrosis or sloughing of epithelial cells was detected in histological studies. Keywords: cellular cytotoxicity, drug-release, erlotinib, PEGylation liposomes, pharmacokinetic

We report on the phase behavior of a technical grade and commercially available diglycerol monoisostearate, C41V, and its use for the preparation of nanostructured liquid crystal dispersions (hexosomes). C41V in water forms a reverse hexagonal liquid crystal at room temperature and in a wide range of concentrations (0.5–95 wt%); this hexagonal liquid crystal is stable up to 70 °C. A simple and effective method has been developed to disperse hexosomes with an encapsulated active molecule (Ketoprofen) that consists of (1) producing a nano-emulsion stabilized by an amphiphilic block copolymer (Pluronic F127) and containing ethyl acetate and C41V by using ultrasounds and (2) evaporating the solvent to produce hexosomes. The size of the hexosomes and ultrasound dispersion time is markedly reduced by using ethyl acetate as an auxiliary solvent with an optimal initial ratio of C41V:ethyl acetate of 50:50. Dynamic light scattering shows that the size of the hexosomes decreases as the concentration of stabilizer F127 or encapsulated Ketoprofen is increased. The lattice parameter in the hexagonal structure is calculated from small angle scattering data to be ca. 5.3 nm and is only slightly dependent on the amount of F127 and/or encapsulated Ketoprofen. Cryo electron microscopy reveals that the samples contain hexosomes and these coexist with spherical, likely F127 micelles. Lastly, hexosomes show a pH responsive release of Ketoprofen which could be useful for target delivery in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Fibrous membranes of poly(ɛ-caprolactone)/γ-poly(glutamicacid) (PCL/γ-PGA) composites were successfully produced via an electrospinning process. In doing so, the water solubility of florfenicol (FF) could be enhanced and the drug release properties of FF could be controlled. The mechanical, morphologic, and thermal properties of the fibrous membranes of PCL/γ-PGA were studied by using an electronic single fiber strength machine, scanning electron microscopy, and differential scanning calorimetry. The wettability of the fibrous membranes of PCL/γ-PGA was also measured as discussed in the subsequent section. Fourier transform infrared spectroscopy was applied in the structural analysis of the PCL/γ-PGA-FF fibrous membranes. The results indicated that FF was well blended in the composite membranes of PCL/γ-PGA. In vitro dissolution tests showed that PCL/γ-PGA (85/15; 8%) as both a biodegradable and biocompatible blend may improve the solubility of FF. Therefore, fibrous membranes of PCL/γ-PGA may represent ideal materials for the controlled drug release in various clinical applications. [ABSTRACT FROM AUTHOR]

A series of poly(acrylic acid-co-methylvinylketone-graft-sulfamethoxazole)(AVMDS) species was synthesized for drug carrier applications. The synthesis involved two steps: copolymerization of acrylic acid(AA) with methyl vinyl ketone(MVK) through the free radical route and subsequent grafting of the sulfamethoxazole (SMX) onto the copolymer via the Schiff base reaction of the primary amine of SMX with the carbonyl groups of the MVK units. The structures and properties of the materials were characterized by nuclear magnetic resonance(NMR), X-ray diffraction(XRD), differential scanning calorimetry(DSC), and scanning electronic microscopy (SEM). An in-vitro cytotoxicity test of the drug-carrier systems via MTT assay revealed no significant cytotoxic effect at concentrations up to 100 µg · ml−1. The dynamic release of SMX from these systems through a retro-imidation reaction (inverse Schiff base reaction) was investigated in depth, where the diffusion through the polymer matrix, the enhancement of the water solubility of SMX, the influence of the initial drug concentration, the pH of the medium, and the effect of the degree of swelling of the polymer matrix on the release dynamics were evaluated. The AVMGS4 and AVMGS1 drug carrier systems containing 3.58 and 1.18 wt% of SMX were the best performing systems. [ABSTRACT FROM AUTHOR]

A new pH-sensitive system designed for drug-delivery purposes and based on functionalized multiwall magnetic carbon nanotubes (Mag-CNTs) was synthesized for the effective incorporation of non-steroidal anti-inflammatory drugs (NSAIDs), aiming at drug release in characteristic acidic conditions close to the actual conditions of inflamed tissues. Cationic hyperbranched polyethyleneimine (PEI) was immobilized on the surface of Mag-CNTs via electrostatic interactions between the positively charged protonated amines within the polymer and the carboxyl groups on the chemically oxidized Mag-CNT surface. The addition of the NSAID with a carboxylate donor, Naproxen (NAP), was achieved by indirect coupling through the amino groups of the intermediate linker PEI. FT-IR, Raman, and UV–vis spectroscopy were employed to fully characterize the synthesized nanocarrier and its functionalization procedure. The interaction of the designed nanocarrier with bovine serum albumin (BSA) was studied in vitro by fluorescence emission spectroscopy while its in vitro interaction with calf-thymus (CT) DNA was monitored by UV–vis spectroscopy and viscosity measurements and via competitive studies with ethidium bromide. The calculated binding constants were compared to those of free NAP revealing a higher binding affinity for BSA and CT DNA. Finally, drug-release studies were performed, revealing that the electrostatic linkage ensures an effective release of the drug in the acidic pH typical of inflamed cells, while maintaining the multiwall nanotubes (MWNTs)–drug conjugates stable at the typical bloodstream.

Graphical abstract Highlights • Antibacterial and biodegradable polyazomethine hydrogels were successfully prepared. • To investigate usability of the hydrogels as biomaterials, water uptake capacity, drug loading or release performance, protein absorption, biodegradability and antibacterial properties were studied. • The drug loading capacity of melamine-based hydrogels was found in the range from 21.55 and 17.05 µg/mL. Abstract In the present paper, a new series of biodegradable poly(azomethine) gels were prepared to investigate the usability as biomaterials. The structures of the hydrogels were characterized by using FT-IR and SEM analyses. Contact angle measurements were also performed to investigate hydrophobicity of the hydrogels. Thermal behavior of melamine-based poly(azomethine)s and hydrogels was performed using TG-DTA and DSC techniques. Mechanical properties of poly(azomethine) hydrogels were investigated using a tensile testing method. Biodegradability, drug loading or release performance, protein absorption, water uptake and antibacterial properties were also studied due to investigate usability of melamine-based hydrogels as biomaterials. [ABSTRACT FROM AUTHOR]

Light-triggered drug delivery system is an effective strategy for precise diagnosis and therapy in cancer treatment. However, it suffers from difficultly balancing the dosimetry of drug with light dose and a lack of in vivo models for validating their clinical benefits. Here we report an unprecedented near-infrared (NIR) light photocaged cyanine-based prodrug Cy-CPT-Biotin with dual-channel fluorescence mode, enabling NIR light to precisely regulate where, when and how the intact and active prodrugs are delivered. The synergy of photochemical reaction and modulation in π-conjugated polyene backbone of cyanine can fully perform distinct dual-channel fluorescence changes in a NIR light-mediated manner. The prodrug has striking characteristics of excellent tumor-targeting ability, real-time monitoring of the in vivo behaviors by dual-channel mode and NIR-light triggering, especially for achieving fine regulation and on-demand drug release in the precise dosimetry of drug with light dose in living animals. This optical orthogonality strategy that conjuncts with NIR light-triggered and dual-channel fluorescence in vivo imaging provides a powerful tool for in vivo real-time tracking and finely tuning the prodrug release for precise drug delivery. [ABSTRACT FROM AUTHOR]

In the present study, novel pH-responsive prodrug nanoparticles based on xylan-curcumin (xyl-cur) conjugate were developed to enhance the therapeutic efficacy of curcumin in cancer therapy. The synthesis of xyl-cur conjugate (prodrug) was confirmed by FT-IR, 1 H NMR, UV–vis and fluorescence spectroscopy. The xyl-cur prodrug was subsequently self-assembled in to nanoparticles (xyl-cur prodrug NPs) in an aqueous medium with the average particle size 253 nm and the zeta potential of −18.76 mV. The xyl-cur prodrug NPs were highly pH-sensitive in nature and most of the drug was released at lower pH. The interaction of the xyl-cur prodrug NPs with blood components was tested by hemolysis study. The cytotoxic activity of the xyl-cur prodrug NPs against human colon cancer cells (HT-29, HCT-15) demonstrated that the prodrug NPs exhibits greater cytotoxic effect than curcumin. Therefore, these results reveal that xyl-cur prodrug NPs could be a promising candidate for improving the intracellular delivery of curcumin in cancer therapy. [ABSTRACT FROM AUTHOR]

Multifunctional surfaces may display the potential to accelerate and promote the healing process around dental implants. However, the initial cellular biocompatibility, molecular activity, and the release of functionalized molecules from these novel surfaces require extensive investigation for clinical use. Aiming to develop and compare innovative surfaces for application in dental implants, the present study utilized titanium disks, which were treated and divided into four groups: machined (Macro); acid-etched (Micro); anodized-hydrophilic surface (TNTs); and anodized surface coated with a rifampicin-loaded polymeric layer (poly(lactide-co-glycolide), PLGA) (TNTsRIMP). The samples were characterized regarding their physicochemical properties and the cumulative release of rifampicin (RIMP), investigated at different pH values. Additionally, differentiated osteoblasts from mesenchymal cells were used for cell viability and qRT-PCR analysis. Antibacterial properties of each surface treatment were investigated against Staphylococcus epidermidis. TNTsRIMP demonstrated controlled drug release for up to 7 days in neutral pH environments. Osteogenic cell cultures indicated that all the evaluated surfaces showed biocompatibility. The TNTs group revealed up-regulated values for bone-related gene quantification in 7 days, followed by the TNTsRIMP group. Furthermore, the antibiotic-functionalized surface revealed effectiveness to inhibit S. epidermidis and stimulate promising conditions for osteogenic cell behavior. Characteristics such as nanomorphology and hydrophilicity were determinants for the up-regulated quantification of osteogenic biomarkers related to early bone maturation, encouraging application in intra-osseous implant surfaces; in addition, antibiotic-functionalized surfaces demonstrated significant higher antibacterial properties compared to the other groups. Our findings suggest that polymeric-antibiotic-loaded coating might be applied for the prevention of early infections, favoring its application in multifunctional surfaces for intra- and/or trans-mucosal components of dental implants, while, hydrophilic nanotextured surfaces promoted optimistic properties to stimulate early bone-related cell responses, favoring its application in bone-anchored surfaces. [Display omitted] • Macro-, micro-, and nano-topographies were developed for application on dental implant surfaces. • An antibiotic-release coating demonstrated biocompatibility and successful antibacterial properties. • Hydrophilic nanotextured surfaces showed optimistic properties for intra-osseous surfaces. • The drug-release coating revealed promising properties to defend against early contamination in the trans-mucosal region. • Particular combinations of surface properties may perform favorable actions on different regions of dental implants. [ABSTRACT FROM AUTHOR]

Stimuli-responsive, drug-loaded, DNA-based nano- and micro-capsules attract scientific interest as signal-triggered carriers for controlled drug release. The methods to construct the nano-/micro-capsules involve i) the layer-by-layer deposition of signal-reconfigurable DNA shells on drug-loaded microparticles acting as templates, followed by dissolution of the core templates; ii) the assembly of three-dimensional capsules composed of reconfigurable DNA origami units; and iii) the synthesis of stimuli-responsive drug-loaded capsules stabilized by DNA−polymer hydrogels. Triggers to unlock the nano-/micro-capsules include enzymes, pH, light, aptamer−ligand complexes, and redox agents. The capsules are loaded with fluorescent polymers, metal nanoparticles, proteins or semiconductor quantum dots as drug models, with anti-cancer drugs, e.g., doxorubicin, or with antibodies inhibiting cellular networks or enzymes over-expressed in cancer cells. The mechanisms for unlocking the nano-/micro-capsules and releasing the drugs are discussed, and the applications of the stimuli-responsive nano-/micro-capsules as sense-and-treat systems are addressed. The scientific challenges and future perspectives of nano-capsules and micro-capsules in nanomedicine are highlighted. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to evaluate the antibacterial effect of a drug releasing poly (3-hydroxybutyrate) (P(3HB)) implant coating in comparison to pure titanium on Aggregatibacter actinomycetemcomitans as a model periodontopathogen to prevent biofilm formation on implant surfaces. Methods: Titanium discs were coated with P(3HB) containing 5% (w) and 10% (w) of metronidazole, either with and without a P(3HB) topcoat. The biofilm formation was evaluated after 1, 4 and 9 days in a dynamic flow chamber system. Microbial adherence was quantified by determination of bacterial surface coverage. Results: The evaluated formulations of P(3HB)/metronidazole showed an antibacterial effect especially in the first 24 h. Prolonged incubation for 9 days showed reduced bacterial adhesion only on polymer coatings loaded with 10% (w) of metronidazole both with and without topcoat. Conclusions: The evaluated coating formulations can provide protection from an Aggregatibacter actinomycetemcomitans in vitro biofilm formation for the time period which was evaluated. [ABSTRACT FROM AUTHOR]

Bioactive titania (TiO 2 ) microparticles can be used as drug-releasing cement fillers for the chemotherapeutic treatment of metastatic bone tumors. Porous anatase-type TiO 2 microspheres around 15 μm in diameter were obtained through a sol–gel process involving a water-in-oil emulsion with 30:70 SiO 2 /H 2 O weight ratio and subsequent NaOH solution treatment. The water phase consisted of methanol, titanium tetraisopropoxide, diethanolamine, SiO 2 nanoparticles, and H 2 O, while the oil phase consisted of kerosene, Span 80, and Span 60. The resulting microspheres had a high specific surface area of 111.7 m 2 ·g − 1 . Apatite with a network-like surface structure formed on the surface of the microspheres within 8 days in simulated body fluid. The good apatite-forming ability of the microspheres is attributed to their porous structure and the negative zeta potential of TiO 2 . The release of rhodamine B, a model for a hydrophilic drug, was rapid for the first 6 h of soaking, but diffusion-controlled thereafter. The burst release in the first 6 h is problematic for clinical applications; nonetheless, the present results highlight the potential of porous TiO 2 microspheres as drug-releasing cement fillers able to form apatite. [ABSTRACT FROM AUTHOR]

In this study, gentamicin loaded collagen I/hyaluronic acid multilayers modified titanium coating (TC-AA(C/H) 6 -G) was fabricated via a layer-by-layer (LBL) covalent immobilization method. The drug releasing properties of collagen I/Hyaluronic acid (Col-I/HA) multilayers and the effect of loaded gentamicin on the antibacterial properties and cytocompatibility of modified TC were investigated. The gentamicin release assay indicated that the Col-I/HA multilayers modified TC exhibited agreeable drug-loading amount (537.22 ± 29.66 µg of gentamicin) and controlled-release performance (240 h of sustained release time). TC-AA(C/H) 6 -G revealed satisfactory antibacterial activity and inhibited the colonization and biofilm formation of S. aureus . Fortunately, the functions of hMSCs on TC-AA(C/H) 6 -G did not affected by the loaded gentamicin, and TC-AA(C/H) 6 -G could improve the adhesion, proliferation and osteogenic differentiation of cells, as well as TC-AA(C/H) 6 . In vivo animal study indicated that TC-AA(C/H) 6 -G could effectively control intramedullary cavity infection caused by S. aureus and prevent bone destruction., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ma, Zong, Xun, Hu, Chen, Zhang, Peng, Song and Ao.)

Abstract: It is desired that the coatings on metallic implants have both excellent biological responses and good loading-release capacities of biological factors or drugs. So far, the challenge still remains, because the morphology and composition of the bioactive coatings are usually not favorable for accommodating drug molecules. In this study, we adopted an approach of incorporating chitosan nanospheres into a thin mineralized collagen coating; this approach is based on the good loading–release behavior of the nanospheres and the good cytocompatibility of the thin coating. The incorporation of chitosan nanospheres into the mineralized collagen coatings was realized by electrolytic co-deposition. The morphologies and microstructures of the resulting coatings were characterized by SEM, and the phase and chemical compositions of the coatings were measured by XRD and FTIR. The loading–release capacity for vancomycin hydrochloride (VH) was determined by ultraviolet spectrophotometry. MTS assay was used to evaluate cytocompatibility, and in vitro bacterial adhesion was tested for assessing the antibacterial effects of the VH-loaded coatings. The chitosan nanospheres adhered tightly to collagen fibrils. The incorporated coatings facilitated the sustained release of VH, and had a clear antibacterial effect. The incorporation of chitosan nanospheres into mineralized collagen coatings demonstrates an effective way to improve the drug loading–release capacity for the thin coatings. This formulation had a highly effective biological response. [Copyright &y& Elsevier]

A mono-substituted resveratrol derivative, resveratrol-modified stearate (RMS), was synthesized by selectively coupling of stearic acid to the monohroxyphenyl of resveratrol in order to enhance both the stability and bioavailability of resveratrol. The RMS self-assembles into liposomes and a series of suprastructural transformations into metastable helical ribbon, linear wire-like structures, and inert spherical nanoparticles were detected that may be induced by the hydrogen-bonding interactions. As a model for drug-release investigations, gold nanoparticles (AuNPs) were encapsulated successfully by RMS to generate vesicles and succeed to release AuNPs druing the transformation to a ribbon-like metastable stucture at ambient temperature. [ABSTRACT FROM AUTHOR]

Abstract: Multifunctional hydrogels that simultaneously possess semi-interpenetrating networks structure, strong photoluminescence, and temperature sensitivity were successfully fabricated based on the crosslink of poly(acrylamide) (PAAm) in the presence of poly(N-isopropylacrylamide) (PNIPAM) and CdTe quantum dots (QDs) at a mild condition. With the increase of external temperature, the photoluminescence (PL) intensity and emission peak of the hydrogels gradually decreased and red-shifted, respectively. Decreasing the temperature, the PL intensity and emission peak of the hydrogels could back to their initial values again. Moreover, drug-release experiments on the multifunctional hydrogels demonstrated that the release rate can be tuned by the environmental temperature and the content of PNIPAM. In addition, biocompatible hyperbranched polyglycerol functionalized QDs (QD@HPGs) instead of pristine QDs can also be incorporated into the hydrogels, affording biocompatible hydrogels which could still exhibit temperature-sensitive photoluminescence and drug-release behaviors. [Copyright &y& Elsevier]

Polymeric materials are clinically required for medical devices, as well as controlled drug delivery systems. Depending on the application, the polymer has to provide suitable functionalities, for example, mechanical functions or the capability to actively move, so that an implant can be inserted in a compact shape through key-hole incisions and unfold to its functional shape in the body. Shape-memory polymers, as described herein regarding their general principle, compositions and architectures, have developed to a technology platform that allows the tailored design of such multifunctionality. In this way, defined movements of implants triggered either directly or indirectly, tailored mechanical properties, capability for sterilization, biodegradability, biocompatibility and controlled drug release can be realized. This comprehensive review of the scientific and patent literature illustrates that this technology enables the development of novel medical devices that will be clinically evaluated in the near future. INSET: Key issues. [ABSTRACT FROM AUTHOR]

The application of iontophoresis was demonstrated in the nail drug delivery of terbinafine (TH) recently. This study explored a systematic assessment of this approach to enhance the drug delivery using a novel topical formulation, and the subsequent release of TH from the drug loaded nails. For the first time, a nail on-agar plate model was used to study the release of drug from the iontophoresis (0.5 mA/cm2) loaded nails. In addition, the activity of the drug released from the drug loaded nail plate was studied against Trichophyton rubrum. An increase in applied current density and current duration enhanced the transport of TH into and through the nail plate. In vitro release of drug from the iontophoretic loaded nails into agar plates exhibited 2-phase release pattern. The amount of drug released in both of the in vitro models was comparable, and the nails loaded using iontophoresis continued to release levels of TH > 2 orders of magnitude above the minimum inhibitory concentration over at least 52 days. Results indicate that iontophoresis enhances the delivery of terbinafine into and through the nail plate and suggest that the use of this treatment approach could result in a safe and more efficacious outcome with less frequent treatments. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4130–4140, 2009 [ABSTRACT FROM AUTHOR]

Abstract: The properties of -dialkyl chitosan monolayers and corresponding vesicles have been studied by LB technique and drug-release experiment. With increasing molecular weight of chitosan backbone and/or length of alkyl chain, both the compressibility and collapse pressure of -dialkyl chitosan monolayer are enhanced. The experiments on drug-release behavior of -dialkyl chitosan vesicles show that the drug-release rate and the equilibrium drug-release ratio are decreased with increasing the compressibility of corresponding monolayer. It is worth noticing that there is a linear relationship between the compressibility of -dialkyl chitosan monolayers and the equilibrium drug-release ratio of the vesicles. [Copyright &y& Elsevier]

We have synthesized various types of poly(ethylene glycol) (PEG)-ibuprofen conjugates by nucleophilic substitution of bromo-terminated PEG with ibuprofen-Cs salt. The conversion of the terminal hydroxyl groups to bromo-termini was quantitative, as was the drug conjugation process, which suggests that the present synthetic method is very useful for the preparation of PEG-based prodrugs from pharmaceuticals having carboxyl functionalities. The drug-release behavior of the prodrugs was examined in both phosphate buffer (PBS, pH 7.4) and rat plasma. From the drug-release behavior in PBS, we determined that each prodrug has high storage stability. The drug-release rate was observed to be much faster in rat plasma than in buffer solution as a result of the acceleration effect provided by enzymes present in the plasma. The drug-release rate in rat plasma depends on the degree of molecular aggregation of the prodrugs, which can be changed effectively by the nature of their spacer groups or by the use of Pluronic as the polymer carrier. [ABSTRACT FROM AUTHOR]

Ciprofloxacin albumin microspheres were prepared by the spray drying technique, with bovine serum albumin as the natural biodegradable wall material. The spherical microspheres, flowed well, were organic solvent free and in the size range 1 ~ 5 μm. The drug release from the microspheres could be retarded by further thermal denaturation. The sustained-release microspheres were suitable for dry powder inhaled lung drug delivery systems. [ABSTRACT FROM AUTHOR]

• The gelation process of TOCN and TOChN was optimized that improved the production efficiency. • The release of amygdalin from hydrogel could be more than 60 h with a release amount of 80 %. • The release capacity of hydrogels showed diversity due to the different pH surroundings. Cellulose and chitin, as the two important natural carbohydrate polymers, have possibility to disassemble to biomass derived polysaccharide nanofibers. The 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidized nanocellulose and nanochitin based hydrogel was fabricated via acid gas phase coagulation. It was observed that hydrogels began to form when the pH was lower than 3. When 0.1 mL of acetic acid coagulation bath was provided, 10 h were enough to form sufficient physical crosslinking. Moreover, the release time of amygdalin loaded in the hydrogel could be more than 60 h with a release amount of 80 % due to the uniform network and water-bearing structure. Meanwhile, the release capacity of hydrogels showed diversity at different pH surroundings, which was attributed to the existence of carboxyl groups on the oxidized nanofiber. The results suggested the possible application of the produced nanofiber hydrogels in some specific areas, such as drug delivery, wound dressing, and food packaging. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is a natural polymer with properties suitable for tissue engineering and possible applications in scaffold production. However, current procedures have limitations in obtaining BC pellicles with the desired structural, physical, and mechanical properties. Thus, this study analyzed the optimal culture conditions of BC membranes and two types of processing: draining and oven-drying. The aim was to obtain BC membranes with properties suitable for a wound dressing material. Two studies were carried out. In the preliminary study, the medium (100 mL) was inoculated with varying volumes (1, 2, 3, 4, and 5 mL) and incubated statically for different periods (3, 6, 9, 12, and 18 days), using a full factorial experimental design. Thickness, uniformity, weight, and yield were evaluated. In the optimization study, a Box–Behnken design was used. Two independent variables were used: inoculum volume (X1: 1, 3, and 5 mL) and fermentation period (X2: 6, 12, and 18 d) to determine the target response variables: thickness, swelling ratio, drug release, fiber diameter, tensile strength, and Young's modulus for both dry and moist BC membranes. The mathematical modelling of the effect of the two independent variables was performed by response surface methodology (RSM). The obtained models were validated with new experimental values and confirmed for all tested properties, except Young's modulus of oven-dried BC. Thus, the optimal properties in terms of a scaffold material of the moist BC were obtained with an inoculum volume of 5% (v/v) and 16 d of fermentation. While, for the oven-dried membranes, optimal properties were obtained with a 4% (v/v) and 14 d of fermentation. [ABSTRACT FROM AUTHOR]