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Bitter orange is a citrus fruit rich in bioactive compounds, but its waste is currently underutilized. One potential solution is to encapsulate these bioactive compounds. This research aims to synthesize gelatin nanoparticles loaded with an ethanolic extract of bitter orange peel and to evaluate their in vitro antioxidant and antibacterial activities. Coaxial electrospray was used to encapsulate the ethanolic extract of bitter orange with bovine gelatin as wall material, considering a voltage of 15 kV, a wall solution flow rate of 0.1 mL/h, and a core solution flow rate of 0.08 mL/h. Characterization of the nanoparticles was performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Antioxidant activity was evaluated by the total phenolic content, flavonoids, and antioxidant capacity by the DPPH•, ABTS•+, and FRAP assays. Antibacterial activity was assessed by the well diffusion technique on Mueller–Hinton agar against Listeria monocytogenes and Escherichia coli O157:H7 bacteria. SEM images confirmed that the nanoparticles were spherical in shape, while FT-IR analysis indicated that the incorporation of the extract did not alter the amide bonds of the gelatin protein. The nanoparticles containing the extract exhibited higher antioxidant activity and heightened inhibition against E. coli O157:H7, indicating their potential food applications. [ABSTRACT FROM AUTHOR]

This study reports the successful synthesis of core-shell microparticles utilizing coaxial electrospray techniques, with zeolitic imidazolate framework-8 (ZIF-8) encapsulating rhodamine B (RhB) in the core and a phase change material (PCM) shell composed of a eutectic mixture of lauric acid (LA) and stearic acid (SA). ZIF-8 is well-recognized for its pH-responsive degradation and biocompatibility, making it an ideal candidate for targeted drug delivery. The LA-SA PCM mixture, with a melting point near physiological temperature (39 °C), enables temperature-triggered drug release, enhancing therapeutic precision. The structural properties of the microparticles were extensively characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Drug release studies revealed a dual-stimuli response, where the release of RhB was significantly influenced by both temperature and pH. Under mildly acidic conditions (pH 4.0) at 40 °C, a rapid and complete release of RhB was observed within 120 h, while at 37 °C, the release rate was notably slower. Specifically, the release at 40 °C was 79% higher than at 37 °C, confirming the temperature sensitivity of the system. Moreover, at physiological pH (7.4), minimal drug release occurred, demonstrating the system's potential for minimizing premature drug release under neutral conditions. This dual-stimuli approach holds promise for improving therapeutic outcomes in cancer treatment by enabling precise control over drug release in response to both pH and localized hyperthermia, reducing off-target effects and improving patient compliance. [ABSTRACT FROM AUTHOR]

Cancer is one of the major threats to human health and lives. However, effective cancer treatments remain a great challenge in clinical medicine. As a common approach for cancer treatment, chemotherapy has saved the life of millions of people; however, patients who have gone through chemotherapy often suffer from severe side effects owing to the inherent cytotoxicity of anti-cancer drugs. Stabilizing the blood concentration of an anti-cancer drug will reduce the occurrence or severity of side effects, and relies on using an appropriate drug delivery system (DDS) for achieving sustained or even on-demand drug delivery. However, this is still an unmet clinical challenge since the mainstay of anti-cancer drugs is small molecules, which tend to be diffused rapidly in the body, and conventional DDSs exhibit the burst release phenomenon. Here, we establish a class of DDSs based on biodegradable core–shell microspheres with encapsulated doxorubicin hydrochloride-loaded gold nanoparticles (DOX@Au@MSs), with the core–shell microspheres being made of poly(lactic-co-glycolic acid) in the current study. By harnessing the physical barrier of the biodegradable shell of core–shell microspheres, DOX@Au@MSs can provide a sustained release of the anti-cancer drug in the test duration (which is 21 days in the current study). Thanks to the photothermal properties of the encapsulated gold nanoparticle carriers, the core–shell biodegradable microspheres can be ruptured through remotely controlled near-infrared (NIR) light, thereby achieving an NIR-controlled triggered release of the anti-cancer drug. Furthermore, the route of the DOX-Au@MS-enabled controlled release of the anti-cancer drug can provide durable cancer cell ablation for the long period of 72 h. [ABSTRACT FROM AUTHOR]

Vancomycin in sustained release still needs to be investigated. Polylactic acid (PLA) was widely used in the biomedical field for its good biocompatibility, especially in the field of controlled drug release. In this study, polyethylene glycol (PEG) was used to modify PLA to improve the hydrophilicity of the material. The synthesis of the block copolymers was proven by infrared and nuclear magnetic characterization and the hydrophilicity was tested. Vancomycin was immobilized by coaxial electrospray, and PLA-PEG6000-PLA was used as the shell layer. The parameters of coaxial electrospray under this material were explored, and the effects of concentration, voltage and temperature on the formation of microspheres were systematically studied. The optimum parameters were determined as follows: concentration 20 wt%, temperature 35 °C and voltage 14 kV. The maximum encapsulation rate and drug loading were calculated to be 89.54 ± 1.22 % and 15.33 ± 0.97 %, respectively, and the cumulative release of drug-loaded microspheres was less than 45 % in 24 h with a slow releasing time of more than one month. The drug loaded microspheres showed good sustained release and good control of burst release. [ABSTRACT FROM AUTHOR]

Berberine (BBR) has many pharmacological activities including anti-inflammatory, antibacterial, and against many diseases, especially cancer. However, berberine is a large molecular compound with rapid metabolism by enzymes in the human body and limited bioavailability. To improve, berberine needs to be coated and combined with other active ingredients. In this study, berberine is successfully encapsulated by coaxial electrosprayed chitosan (CS) without cross-linked agents, and piperine (PPR) is also added via two different approaches to improve absorption and bioavailability. The obtained nanoparticles have a spherical shape with smooth surface and relatively wide particle size distribution observed by SEM. The uniform core/shell structure with clear boundary, non-agglomerated encapsulated spheres, and average diameter of 143.67 ± 56.16 nm (for BBR-PPR@CS) and 152.91 ± 48.50 nm (for BBR@PPR-CS) were analyzed by TEM images. The appearance of some weak peaks and slight shifting of major peaks in FTIR spectra of BBR-PPR@CS and BBR@PPR-CS samples and their high encapsulation efficiencies reflected their successful encapsulation. In drug release experiments, as expected, with the combination of PPR and CS in the outer shell (BBR@PPR-CS), the release of PPR was faster than that of BBR. The amount of drug in all samples was released more strongly at pH 5.0 than at pH 7.4, and the release time extended up to 36 h. Therefore, coaxial electrosprayed chitosan nanoparticle is a promising functional material for the simultaneous encapsulation of BBR and PPR, as well as increasing bioavailability of BBR, contributing to the development of controlled drugs toward effective anticancer. [ABSTRACT FROM AUTHOR]

The encapsulation and the oxidative stability of cod liver fish oil (CLO) within coaxial electrosprayed (ethyl cellulose/CLO) core–(octenyl succinic anhydride, OSA-modified starch) shell, and monoaxial electrosprayed ethyl cellulose/CLO microcapsules were investigated. Core–shell (H-ECLO) and monoaxial (ECLO) electrosprayed microcapsules with an average diameter of 2.8 ± 1.8 µm, and 2.2 ± 1.4 µm, respectively, were produced. Confocal microscopy confirmed not only the core–shell structure of the H-ECLO microcapsules, but also the location of the CLO in the core. However, for the ECLO microcapsules, the CLO was distributed on the microcapsules' surface, as also confirmed by Raman spectroscopy. Atomic force microscopy showed that the average surface adhesion of the H-ECLO microcapsules was significantly lower (5.41 ± 0.31 nN) than ECLO microcapsules (18.18 ± 1.07 nN), while the H-ECLO microcapsules showed a remarkably higher Young's modulus (33.84 ± 4.36 MPa) than the ECLO microcapsules (6.64 ± 0.84 MPa). Differential scanning calorimetry results confirmed that the H-ECLO microcapsules enhanced the oxidative stability of encapsulated CLO by about 15 times, in comparison to non-encapsulated oil, mainly by preventing the presence of the fish oil at the surface of the microcapsules, while ECLO microcapsules enhanced the oxidative stability of CLO about 2.9 times due to the hydrophobic interactions of the oil and ethyl cellulose. Furthermore, the finite element method was also used to evaluate the electric field strength distribution, which was substantially higher in the vicinity of the collector and lower in the proximity of the nozzle when the coaxial electrospray process was employed in comparison to the monoaxial process. [ABSTRACT FROM AUTHOR]

To improve the antitumor effect of combined capecitabine (CAP) and osimertinib (OSI) therapy and quickly and efficiently reduce tumor volumes for preoperative chemotherapy, we designed a compound CAP colon-targeted microparticle (COPMP) prepared by coaxial electrospray. COPMP is a core–shell microparticle composed of a Eudragit S100 outer layer and a CAP/OSI-loaded PLGA core. In this study, we characterized its size distribution, drug loading (DL), encapsulation efficiency (EE), differential scanning calorimetry (DSC), Fourier transform infrared spectra (FTIR), in vitro release, formula ratio, cellular growth inhibition, and in vivo antitumor efficacy. COPMP is of spherical appearance with a size of 1.87 ± 0.23 μm. The DLs of CAP and OSI are 4.93% and 4.95%, respectively. The DSC showed that the phase state of CAP and OSI changed after encapsulation. The FTIR results indicated good compatibility between the drug and excipients. The release curve showed that CAP and OSI were released in a certain ratio. They were barely released prior to 2 h (pH 1.0), less than 50% was released between 3 and 5 h (pH 6.8), and sustained release of up to 80% occurred between 6 and 48 h (pH 7.4). CAP and OSI demonstrated a synergistic effect on HCT-116 cells. In a colon tumor model, the tumor inhibition rate after oral administration of COPMP reached 94% within one week. All the data suggested that COPMP promotes the sustained release of CAP and OSI in the colon, which provides a preoperative chemotherapy scheme for the treatment of colon cancer. [ABSTRACT FROM AUTHOR]

Background: The oral colon-targeting drug delivery vehicle is vital for the efficient application of curcumin (Cur) in ulcerative colitis (UC) treatment because of its lipophilicity and instability in the gastrointestinal tract. Methods: The core–shell microparticle (MP) system composed of eco-friendly materials, zein and shellac, was fabricated using a coaxial electrospray technique. In this manner, Cur was loaded in the zein core, with shellac shell coating on it. The colon-targeting efficiency and accumulation capacity of shellac@Cur/zein MPs were evaluated using a fluorescence imaging test. The treatment effects of free Cur, Cur/zein MPs, and shellac@Cur/zein MPs in acute experimental colitis were compared. Results: With the process parameters optimized, shellac@Cur/zein MPs were facilely fabricated with a stable cone-jet mode, exhibiting standard spherical shape, uniform size distribution (2.84 ± 0.15 µm), and high encapsulation efficiency (95.97% ± 3.51%). Particularly, with the protection of shellac@zein MPs, Cur exhibited sustained drug release in the simulated gastrointestinal tract. Additionally, the in vivo fluorescence imaging test indicated that the cargo loaded in shellac@zein MPs improves the colon-targeting efficiency and accumulation capacity at the colonitis site. More importantly, compared with either free Cur or Cur/zein MPs, the continuous oral administration of shellac@Cur/zein MPs for a week could efficiently inhibit inflammation in acute experimental colitis. Conclusion: The shellac@Cur/zein MPs would act as an effective oral drug delivery system for UC management. [ABSTRACT FROM AUTHOR]

Aim: To reduce the contamination arising from abuse of commercial pesticide formulations, the coaxial electrospray (CES) method was used for one-step microencapsulation and spraying of pesticides. Methods: After optimisation of process parameters, polymeric microcapsules with different structures were fabricated as the carriers of azoxystrobin (AZS). For the resultant microcapsules, the sustained pesticide release was verified in vitro and the adhesion properties were investigated through a normalised rinsing test. Results: The maximum encapsulation efficiency of the fabricated AZS-loaded microcapsules was 99.14%. Compared to commercial AZS aqueous suspension, the microcapsules fabricated by the CES method exhibited improved sustained release performance of AZS, which could be readily controlled by adjusting the shell thicknesses. Moreover, highly enhanced adhesion performance was observed for the AZS-loaded microcapsules directly sprayed in CES process. Conclusions: The CES process is promising to be applied as a one-step microencapsulation and spraying technology for improving pesticide utilisation and reducing environmental pollution. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric core–shell microspheres have been widely applied in dual‐drug release system for their convenience to treat diseases through multiple therapies. In this contribution, acrylamide‐modified chitin (AMC)/chitosan (CS) core–shell microspheres were prepared by a coaxial electrospray method under mild conditions. The dimension of the microspheres and thickness of the layer can be delicately controlled by changing the feed rate of spray solutions and the applied voltage. The core–shell structure of the microspheres was characterized by Fourier transform infrared spectra (FT‐IR), scanning electron microscope (SEM), and stereo fluorescence microscope. To investigate the dual‐drug release behavior of the core–shell microspheres, small molecular FITC‐dextran and macromolecular dextran blue 2000 were chosen as model drugs. The release rate of small molecular FITC‐dextran was higher than macromolecular dextran blue 2000 regardless of the location of FITC‐dextran in the microspheres. The biocompatibility, biodegradability, and dual‐drug release behavior of the core–shell microspheres endow it with potential applications in combination therapies. [ABSTRACT FROM AUTHOR]

Abstract: A temperature‐regulated system for the controlled release of nerve growth factor (NGF) to promote neurite outgrowth is reported. The system is based upon microparticles fabricated using coaxial electrospray, with the outer solution containing a phase‐change material (PCM) and the inner solution encompassing payload(s). When the temperature is kept below the melting point of the PCM, there is no release due to the extremely slow diffusion through a solid matrix. Upon increasing the temperature to slightly pass the melting point, the encapsulated payload(s) can be readily released from the melted PCM. By leveraging the reversibility of the phase transition, the payload(s) can be released in a pulsatile mode through on/off heating cycles. The controlled release system is evaluated for potential use in neural tissue engineering by sandwiching the microparticles, coloaded with NGF and a near‐infrared dye, between two layers of electrospun fibers to form a trilayer construct. Upon photothermal heating with a near‐infrared laser, the NGF is released with well‐preserved bioactivity to promote neurite outgrowth. By choosing different combinations of PCM, biological effector, and scaffolding material, this controlled release system can be applied to a wide variety of biomedical applications. [ABSTRACT FROM AUTHOR]

Alginate-based microencapsulation of cells has made a significant impact on the fields of regenerative medicine and tissue engineering mainly because of its ability to provide immunoisolation for the encapsulated material. This characteristic has allowed for the successful transplantation of non-autologous cells in several clinical trials for life threatening conditions, such as diabetes, myocardial infarction, and neurodegenerative disorders. Methods for alginate hydrogel microencapsulation have been well developed for various types of cells and can generate microcapsules of different diameters, degradation time, and composition. It appears the most prominent and successful method in clinical applications is the coaxial electrospray method, which can be used to generate both homogenous and non-homogeneous microcapsules with uniform size on the order of 100 μm. The present review aims to discuss why alginate hydrogel is an ideal biomaterial for the encapsulation of cells, how alginate-based microcapsules are generated, and methods of modifying the microcapsules for specific clinical treatments. This review will also discuss clinical applications that have utilized alginate-based microencapsulation in the treatment of diabetes, ischemic heart disease, and neurodegenerative diseases. [ABSTRACT FROM PUBLISHER]

The objective of this study was to investigate the combined influence of independent variables in the preparation of folic acid-chitosan-methotrexate nanoparticles (FA-Chi-MTX NPs). These NPs were designed and prepared for targeted drug delivery in tumor. The NPs of each batch were prepared by coaxial electrospray atomization method and evaluated for particle size (PS) and particle size distribution (PSD). The independent variables were selected to be concentration of FA-chitosan, ratio of shell solution flow rate to core solution flow rate, and applied voltage. The process design of experiments (DOE) was obtained with three factors in three levels by Design expert software. Box-Behnken design was used to select 15 batches of experiments randomly. The chemical structure of FA-chitosan was examined by FTIR. The NPs of each batch were collected separately, and morphologies of NPs were investigated by field emission scanning electron microscope (FE-SEM). The captured pictures of all batches were analyzed by ImageJ software. Mean PS and PSD were calculated for each batch. Polynomial equation was produced for each response. The FE-SEM results showed the mean diameter of the core-shell NPs was around 304 nm, and nearly 30% of the produced NPs are in the desirable range. Optimum formulations were selected. The validation of DOE optimization results showed errors around 2.5 and 2.3% for PS and PSD, respectively. Moreover, the feasibility of using prepared NPs to target tumor extracellular pH was shown, as drug release was greater in the pH of endosome (acidic medium). Finally, our results proved that FA-Chi-MTX NPs were active against the human epithelial cervical cancer (HeLa) cells. [ABSTRACT FROM AUTHOR]

BACKGROUND Coaxial electrospray is an emerging technology to produce multilayer micro- and nano-particles ( NPs) with well controlled shape and size. ALA-PDT is a fascinating technology used in the treatment for skin and other cancers. In this work, ALA-loaded poly(lactide-co-glycolide) ( PLGA) ( PLGA-ALA) NPs with high drug loading efficiency were produced via coaxial electrospray and used for the PDT treatment in HSC-3 cells. RESULTS Results showed that 200-1000 nm PLGA-ALA NPs with 60-75% ALA loading efficiency were successfully produced. ALA and PLGA were well integrated and no extra chemical reaction occurred during the electrospray. PLGA-ALA NPs displayed a delayed release of ALA in PBS solution up to 7 days. A massive accumulation of PpIX in HSC-3 cells happened after the incubation of PLGA-ALA NPs. With light irradiation, these PLGA-ALA NPs showed a remarkable cytotoxicity against HSC-3 cells, leading to 40-70% cell death depending on the incubation dose. CONCLUSIONS Coaxial electrospraying is a facile method to prepare PLGA-ALA NPs with high drug loading content and efficiency, and PLGA-ALA NPs turned out to be an effective vehicle for delivering ALA to tumor cells. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Enteric-coated formulations can delay the release of drugs until they have passed through the stomach. However, high concentration of drugs caused by rapidly released in the small intestine leads to the intestinal damage, and frequent administration would increase the probability of missing medication and reduce the patient compliance. To solve the above-mentioned problems, aspirin-loaded enteric-coated sustained-release nanoparticles with core-shell structure were prepared via one-step method using coaxial electrospray in this study. Eudragit L100-55 as pH-sensitive polymer and Eudragit RS as sustained-release polymer were used for the outer coating and inner core of the nanoparticles, respectively. The maximum loading capacity of nanoparticles was 23.66 % by changing the flow rate ratio of outer/inner solutions, and the entrapment efficiency was nearly 100 %. Nanoparticles with core-shell structure were observed via fluorescence microscope and transmission electron microscope. And pH-sensitive and sustained drug release profiles were observed in the media with different pH values (1.2 and 6.8). In addition, mild cytotoxicity in vitro was detected, and the nanoparticles could be taken up by Caco-2 cells within 1.0 h in cellular uptake study. These results indicate that prepared enteric-coated sustained-release nanoparticles would be a more safety and effective carrier for oral drug delivery. [ABSTRACT FROM AUTHOR]

Recent developments in multimodal imaging and image-guided therapy requires multilayered microparticles that encapsulate several imaging and therapeutic agents in the same carrier. However, commonly used microencapsulation processes have multiple limitations such as low encapsulation efficiency and loss of bioactivity for the encapsulated biological cargos. To overcome these limitations, we have carried out both experimental and theoretical studies on coaxial electrospray of multilayered microparticles. On the experimental side, an improved coaxial electrospray setup has been developed. A customized coaxial needle assembly combined with two ring electrodes has been used to enhance the stability of the cone and widen the process parameter range of the stable conejet mode. With this assembly, we have obtained poly(lactide-co-glycolide) microparticles with fine morphology and uniform size distribution. On the theoretical side, an instability analysis of the coaxial electrified jet has been performed based on the experimental parameters. The effects of process parameters on the formation of different unstable modes have been studied. The reported experimental and theoretical research represents a significant step toward quantitative control and optimization of the coaxial electrospray process for microencapsulation of multiple drugs and imaging agents in multimodal imaging and image-guided therapy. [ABSTRACT FROM AUTHOR]

Coaxial electrospray is an electrohydrodynamic process that produces multilayer microparticles and nanoparticles by introducing coaxial electrified jets. In comparison with other microencapsulation/nanoencapsulation processes, coaxial electrospray has several potential advantages such as high encapsulation efficiency, effective protection of bioactivity and uniform size distribution. However, process control in coaxial electrospray is challenged by the multiphysical nature of the process and the complex interplay of multiple design, process and material parameters. This paper reviews the previous works and the recent advances in design, modeling and control of a coaxial electrospray process. The review intends to provide general guidance for coaxial electrospray and stimulate further research and development interests in this promising microencapsulation/nanoencapsulation process. [ABSTRACT FROM AUTHOR]

To optimize the anti-tumor efficacy of combination therapy with paclitaxel (PTX) and imatinib (IMN), we used coaxial electrospray to prepare sequential-release core–shell microparticles composed of a PTX-loaded sodium hyaluronate outer layer and an IMN-loaded PLGA core. The morphology, size distribution, drug loading, differential scanning calorimetry (DSC), Fourier transform infrared spectra (FTIR), in vitro release, PLGA degradation, cellular growth inhibition, in vivo vaginal retention, anti-tumor efficacy, and local irritation in a murine orthotopic cervicovaginal tumor model after vaginal administration were characterized. The results show that such core–shell microparticles were of spherical appearance, with an average size of 14.65 μm and a significant drug-loading ratio (2.36% for PTX, 19.5% for IMN, w/w), which might benefit cytotoxicity against cervical-cancer-related TC-1 cells. The DSC curves indicate changes in the phase state of PTX and IMN after encapsulation in microparticles. The FTIR spectra show that drug and excipients are compatible with each other. The release profiles show sequential characteristics in that PTX was almost completely released in 1 h and IMN was continuously released for 7 days. These core–shell microparticles showed synergistic inhibition in the growth of TC-1 cells. Such microparticles exhibited prolonged intravaginal residence, a >90% tumor inhibitory rate, and minimal mucosal irritation after intravaginal administration. All results suggest that such microparticles potentially provide a non-invasive local chemotherapeutic delivery system for the treatment of cervical cancer by the sequential release of PTX and IMN. [ABSTRACT FROM AUTHOR]