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Successful and effective treatment of different types of infections depends upon fast and selective identification of the microorganisms. Pseudomonas aeruginosa is a Gram-negative bacterium which is involved in a number of human infections and may become life-threatening for immunocompromised persons. Pyocyanin is a unique exotoxin which is exclusively secreted as a virulence factor by P. aeruginosa. In this respect, a nano-assembly, composed of a carbon dot conjugated gold nanocomposite (Au@OPCDPEG) having a size of ∼11.5 ± 1.6 nm, was synthesized and used as both a fluorescence resonance energy transfer (FRET) and a colorimetric sensor for pyocyanin detection. When titrated with increasing concentrations of pyocyanin, Au@OPCDPEG NPs showed ∼1.76 ± 0.12 times increase in fluorescence intensity (at ∼505 nm), whereas three distinct isosbestic points were observed in absorption studies. The limit of detection for pyocyanin was found to be ∼3.04 ± 0.27 μM. It was found that Au@OPCDPEG NPs can selectively recognize pyocyanin even in the presence of other toxins under different biological interference. Real-time P. aeruginosa detection studies suggested the minimum detection limit to be ∼1.5 × 106 cfu ml−1 even in the presence of Staphylococcus aureus contamination in the sample. Confocal studies suggested that Au@OPCDPEG NPs can effectively penetrate P. aeruginosa biofilm under laser irradiation. Overall, the present engineered nanoprobe provides an easy, fast and selective method for the detection of P. aeruginosa in biological samples.

Protein corona (PC) formation remains a major hurdle in the successful delivery of nanomedicines to the target sites. Interacting proteins have been reported to undergo structural changes on the nanoparticle (NP) surface which invariably impacts their biological activities. Such structural changes are the result of opening of more binding sites of proteins to adsorb on the NP surface. The process of conversion of α-helix proteins to their β-sheet enriched counterpart is termed as amyloidosis and in case of PC formation, NPs apparently play the crucial role of being the nucleation centres where this process takes place. Conversely, increasing numbers of artificial nano-chaperones are being used to treat the protein misfolding disorders. Anti-amyloidogenic nanomaterials (NM) have been gaining utmost importance in inhibiting Aβ42 (hallmark peptide for Alzheimer's disease) and Hen egg white lysozyme (HEWL, model protein for systemic amyloidosis) aggregation. Interestingly, in this process, NPs inhibit protein β-sheet enrichment. These two seemingly opposite roles of NPs, propelling confirmatory change onto the smorgasbord of adsorbed native proteins and the ability of NPs in inhibiting amyloidosis creates a paradox, which has not been discussed earlier. Here, we highlight the key points from both the facets of the NP behaviour with respect to their physicochemical properties and the nature of proteins they adsorb onto them to unravel the mystery. BRIEF: Protein corona formation remains a major hurdle in achieving the desired efficacy of nanomedicine. Proteins when interact with nanoparticle (NP) surface, undergo both structural and biological changes. Again, NPs are known to exhibit anti-amyloidogenic behaviour where these play the crucial role of preventing any change in their native structure. Such seemingly different roles of NPs need sincere inquisition.

Inhibition of hen egg white lysozyme (HEWL) and Aβ42 fibrillation have been established as the main models for the treatment of systemic lysozyme amyloidosis and Alzheimer's disease (AD), respectively. Several antiamyloidogenic nanomaterials have been developed over the period; however, their intracellular mechanism of action is still not well understood. In this context, plant-based, gold-conjugated, injectable, hydrophilic cellulose nanoonions (CNOs), viz., DH-CNO (∼60 ± 5 nm) and LC-CNO (∼55 ± 12 nm), were developed from their respective hydrophobic cellulose nanocrystals (DH-CNC and LC-CNC) using a single-step chemical template-mediated process. This unique nanocellulose architecture was chemically and morphologically characterized by various spectroscopic and microscopic techniques. Further, the different biophysical studies documented marked the inhibition/disintegration potential of gold-conjugated LC-CNO against HEWL and Aβ42 peptide aggregation. It was further observed that inhibition of protein fibrillation could be achieved within ∼10 min when the same materials were used under photoirradiation conditions. In vitro protein aggregation studies using HEK293 cells suggested that gold-conjugated LC-CNO could effectively reduce the cellular toxicity via regulation of oxidative stress and ion homeostasis. The outcome of the present study will help in designing cellulose-based novel functional nanochaperones against various neurodegenerative diseases.

Protein aggregation leads to the transformation of proteins from their soluble form to the insoluble amyloid fibrils and these aggregates get deposited in the specific body tissues, accounting for various diseases. To prevent such an aggregation, organic–inorganic hybrid nanocomposites of iron oxide nanoparticle (NP, ∼6.5–7.0 nm)-conjugated cellulose nanocrystals (CNCs) isolated from Syzygium cumini (SC) and Pinus roxburghii (PR) were chemically synthesized. Transmission electron microscopy (TEM) images of the nanocomposites suggested that the in situ-synthesized iron oxide NPs were bound to the CNC surface in a uniform and regular fashion. The ThT fluorescence assay together with 8-anilino-1-naphthalenesulfonic acid, Congo Red, and CD studies suggested that short fiber-based SC nanocomposites showed better inhibition as well as dissociation of human serum albumin aggregates. The TEM and fluorescence microscopy studies supported similar observations. Native polyacrylamide gel electrophoresis results documented dissociation of higher protein aggregates in the presence of the developed nanocomposite. Interestingly, the dissociated proteins retained their biological function by maintaining a high amount of α-helix content. The in vitro studies with HEK-293 cells suggested that the developed nanocomposite reduces aggregation-induced cytotoxicity by intracellular reactive oxygen species scavenging and maintaining the Ca2+ ion-channel. These results indicated that the hybrid organic–inorganic nanocomposite, with simultaneous sites for hydrophobic and hydrophilic interactions, tends to provide a larger surface area for nanocomposite–protein interactions, which ultimately disfavors the nucleation step for fibrillation for protein aggregates.

Tissue engineering (TE) is an emerging field where alternate/artificial tissues or organ substitutes are implanted to mimic the functionality of damaged or injured tissues. Earlier efforts were made to develop natural, synthetic, or semisynthetic materials for skin equivalents to treat burns or skin wounds. Nowadays, many more tissues like bone, cardiac, cartilage, heart, liver, cornea, blood vessels, and so forth are being engineered using 3-D biomaterial constructs or scaffolds that could deliver active molecules such as peptides or growth factors. Nanomaterials (NMs) due to their unique mechanical, electrical, and optical properties possess significant opportunities in TE applications. Traditional TE scaffolds were based on hydrolytically degradable macroporous materials, whereas current approaches emphasize on controlling cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix. This review article gives a comprehensive outlook of different organ specific NMs which are being used for diversified TE applications. Varieties of NMs are known to serve as biological alternatives to repair or replace a portion or whole of the nonfunctional or damaged tissue. NMs may promote greater amounts of specific interactions stimulated at the cellular level, ultimately leading to more efficient new tissue formation. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2433-2449, 2019.

Lectins are defined as a group of nonimmune proteins present mostly in plants (and also in some animals and microorganisms) that are known to bind with carbohydrates (mono- and oligosaccharides) with reversible and specific protein/animal cell agglutinating properties. These proteins are present in sufficient amounts to perform various crucial biological functions, viz., plants for defense, adhesion in bacteria, and in case of animals, binding of different proteins. Due to the efficiency and specificity of lectins to bind with carbohydrates, these are mostly used for various biomedical applications. Different types of carbohydrates get overexpressed in a number of diseases, ultimately acting as biomarkers for those diseases to be detected by the lectins. For getting better output, lectins are conjugated with materials that would provide a base for lectin’s efficacy enhancement. After binding to a specific material, the randomness of the molecule gets decreased, which leads to an increase in the proficiency of the biomolecule. For this purpose, nanoparticles (NPs) act as the best platform for lectin conjugation. In general, the conjugation between the NPs and lectins takes place via covalent and non-covalent binding. All these linkages are preferably used in the binding strategies of these moieties. This binding of lectins to NPs helps to increase the specific targeting ability of the NPs by avoiding any nonspecific interaction. Due to higher specificity, NP-lectin conjugates find enormous applications in biomedical fields. In this chapter, we have tried to provide recent developments about these newly emerged nanoconjugates. A brief discussion is given on different lectin-NP conjugation techniques and its characterization followed by their biomedical applications.

Nanotechnology has given a plethora of nanoparticles (NPs) during the last decades, which have been extensively used in molecular imaging, diagnostics and therapy. Despite recent progress in this area, there are only a few nanoformulations that have entered into clinical trials. We must identify new nanoimaging probes and their targets for therapy, develop new nanoagents for diagnostics, and position them in a clinically useful and cost-effective manner. This chapter summarizes the current status of NPs used as molecular imaging probes, their use in the diagnosis of disease-related analytes, and also their effective use in therapy.

Essential oils (EO), which can be extracted from different edible, therapeutic and herbal plants, have been well known as natural antimicrobial additives. However, it is usually hard to attain high antimicrobial efficacy of these EOs, when these are used in different combinations for the control of foodborne microbes, because of their low solubility in water and interactive binding. Here, we report an optimized oil-in-water (o/w) nanoemulsification process for citral and carvone which generated mean droplet size of 11–19 nm. It was found that nature of surfactant viz., Brij-58 vs leaf extract of Lantana camara (LC) plays crucial role in determining the overall stability and size of the droplets. The screened nanoemulsions (NEs), when stored for long duration, showed minimal decrease in oil content with retention of antioxidant activity. The prepared NEs documented enhanced antibacterial activity compared to pure oils whereas higher degree of killing was observed towards Pseudomonas aeruginosa. The NEs also showed killing of both the bacteria on wound dressing cotton gauze bandages (GB). The outcome of the present study may be used for the development of safe and biocompatible antibacterial agents.

Nanotechnology is one of the emerging field and an important tool for the diagnosis and cure of several diseases. Nanomaterials (NMs), with unique targeting specificities, have already generated a significant amount of interests amongst biomedical researchers. The ease of doing surface functionalization along with convenient encapsulation methodologies for bioactive, make NMs a perfect candidate for drug delivery applications. Kidney diseases are a major health problem throughout the world with more prevalence in developing countries. The major ailments include acute renal injury, chronic kidney disease, renal cancer and end-stage renal disease, having multiple etiologies related to sequential pathophysiological stages. In the past few years, many studies of NMs mainly focused on cancer targeting have accidentally resulted in significant findings related to selective kidney targeting and renal accumulation. Nanotechnological interventions improved drug bioavailability and enabled targeted delivery of drugs to specific tissues, cells, or subcellular compartments. Similarly, NMs based diagnostics with point-of-care solutions have provided early recognition of the specific disease sites with higher resolution and lower limit of detection of the targeted biological analyte. Even after the exponential increase in the funds of nanomedicine research worldwide, reports for treating kidney disorders using NMs, are rather scarce in literature with almost no clinically approved nanoparticles (NPs) available in the market that specifically target the kidney for therapeutic or imaging applications. This paper will review the application of NMs for the treatment of renal diseases and their future prospects.

Nano-theranostics offer remarkable potential for future biomedical technology with simultaneous applications for diagnosis and therapy of disease sites. Through smart and careful chemical modifications of the nanoparticle surface, these can be converted to multifunctional tiny objects which in turn can be used as vehicle for delivering multimodal imaging agents and therapeutic material to specific target sites in vivo. In this sense, bimodal imaging probes that simultaneously enable magnetic resonance imaging and fluorescence imaging have gained tremendous attention because disease sites can be characterized quick and precisely through synergistic multimodal imaging. But such hybrid nanocomposite materials have limitations such as low chemical stability (magnetic component) and harsh cytotoxic effects (fluorescent component) and, hence, require a biocompatible protecting agent. Silica micro/nanospheres have shown promise as protecting agent due to the high stability and low toxicity. This review will cover a full description of MRI-active and fluorescent multifunctional silica micro/nanospheres including the design of the probe, different characterization methods and their application in imaging and treatment in cancer.

Personalized medicine refers to the tailoring of medical treatment to the individual characteristics, needs and preferences of each patient. The concept of such treatment strategies have originated from the observations of the clinicians that patients with identical symptoms may have different illnesses, with different causes and consequently, the medical interventions requires special attention for each individual.

Theragnostic NPs give new hope in simultaneous diagnosis and therapy of a disease at curable stage. Theragnosis is the fundamental requirement of personalized medicine. For successful theragnosis applications, the imaging agents and drugs should be efficiently delivered, resulting in adequate imaging signal or drug concentration in the targeted disease site. The selection of NPs for imaging, diagnosis and therapy was based on their biomimetic features with higher surface to volume ratio of the nanomaterials. The essential properties of nanomedicines involve early and precise diagnosis of clinical conditions providing an efficient treatment without secondary effects. Thus, nanotheragnostic probes are much better than conventional treatments where the diagnosis and therapy are way apart from each other. This chapter briefs about the recent advancement of nanotheragnosis research with future scope and associated hurdles.

A lower rim naphthylidene conjugate of calix[4]arene [L] has been synthesized and characterized, and the structure has been established on the basis of single crystal XRD. The L has been found to be selective toward Zn(2+), which induces appropriate changes in the arms of L so that the N(2)O(2) coordination results in the formation of a tetrahedral complex; namely, [ZnL]. [ZnL] recognizes Asp, Cys, His, and Glu from among the naturally occurring amino acids owing to the protonation and chelating ability of the amino acid and the pi-pi interaction ability of the side chain of the amino acid with [ZnL]. All of these features have been demonstrated oil the basis of fluorescence, absorption, and lifetime measurements. The rechelation of Zn(2+) by the amino acid used in the titration has been demonstrated on the basis of ESI-MS studies in the case of Cys to result in a Zn(2+) complex having either 5- or 6-coordination. [ZnL] has also been shown to be selective toward glutathione and glutathione oxidized, The amino acids present in the proteins also interact with [ZnL], resulting in dechelation of [ZnL] as well as aggregation of the protein, as demonstrated on the basis of absorption and fluorescence spectroscopy and atomic force microscopy. The alpha-helical proteins (namely, albumins) exhibit greater conformational changes, as compared to the beta-sheet proteins (namely, lectins), as studied oil the basis of CD spectroscopy, The aggregation of the proteins when treated with [ZnL] follows a trend: peanut agglutinin < bovine serum albumin < jacalin < human serum albumin. The present studies clearly demonstrated the recognition features of [ZnL] toward Asp, Cys, His, and Glu, and the peptides and proteins containing these by spectroscopy and microscopy studies.