Dual stimuli-responsive and sustained drug delivery NanoSensoGel formulation for prevention of cisplatin-induced ototoxicity.

Cisplatin (CisPt)-induced ototoxicity (CIO) is delineated as a consequence of CisPt-induced intracellular generation of reactive oxygen species (ROS) which can be circumvented by Bucillamine (BUC; an antioxidant drug with sulfhydryl groups) and Diltiazem (DLT, L-type calcium channel blocker). However, its effective accumulation in the Organ of Corti and cell cytoplasm is desired. Therefore, a biocompatible BUC- and DLT-nanoparticles (NPs)-impregnated dual stimuli-responsive formulation (NanoSensoGel) presented here with ROS- and thermo-responsive properties for the sustained and receptive delivery of drugs. The ROS-responsive polypropylene sulfide- methyl polyethylene glycol-2000 (PPS-mPEG2000) polymer was rationally designed, synthesized, and characterized to fabricate BUC- and DLT-loaded PPS-mPEG2000-NPs (BUC- and DLT-NPs). The fabricated BUC- and DLT-NPs showed efficient cellular uptake, intracellular delivery, ROS responsiveness, and cytoprotective effect which was characterized using cellular internalization, intracellular ROS, mitochondrial superoxide, and Caspase 3/7 assays on the House Ear Institute-Organ of Corti-1 (HEI-OC1) cells. The composite NanoSensoGel (i.e., ROS-responsive BUC- and DLT-NPs suspended in the thermo-responsive hydrogel) present in a sol state at room temperature and turned to gel above 33°C, which could be essential for retaining the formulation at the target site for long-term release. The NanoSensoGel showed sustained release of BUC and DLT following Fickian release diffusion kinetics. Overall, a novel NanoSensoGel formulation developed in this study has demonstrated its great potential in delivering therapeutics in the inner ear for prophylactic treatment of CIO, and associated hearing loss.

Light-assisted anticancer photodynamic therapy using porphyrin-doped nanoencapsulates.

Light activatable porphyrinic photosensitizers (PSs) are essential components of anticancer and antimicrobial therapy and diagnostic imaging. However, their biological applications are quite challenging due to the lack of hydrophilicity and biocompatibility. To overcome such drawbacks, photosensitizers can be doped into a biocompatible polymer such as gelatin and further can be used for biomedical applications. Herein, first, a novel A4 type porphyrin PS [5,10,15,20-tetrakis(4-pyridylamidephenyl)porphyrin; TPyAPP] was synthesized via a rational route with good yield. Further, this porphyrin was encapsulated into the gelatin nanoparticles (GNPs) to develop hydrophilic phototherapeutic nanoagents (PTNAs, A4por-GNPs). Notably, the synthesis of such porphyrin-doped GNPs avoids the use of any toxic chemicals or solvents. The nanoprobes have also shown good fluorescence quantum yield demonstrating their applicability in bioimaging. Further, the mechanistic aspects of the anticancer and antimicrobial efficacy of the developed A4por-GNPs were evaluated via singlet oxygen generation studies. Overall, our results indicated porphyrin-doped biodegradable polymeric nanoparticles act as effective phototherapeutic agents against a broad range of cancer cell lines and microbes upon activation by the low-cost LED light.

Co-administration of zinc phthalocyanine and quercetin via hybrid nanoparticles for augmented photodynamic therapy.

The photodynamic anticancer activity of a photosensitizer can be further increased by co-administration of a flavonoid. However, this requires that both molecules must be effectively accumulated at the tumor site. Hence, in order to enhance the activity of zinc phthalocyanine (ZnPc, photosensitizer), it was co-encapsulated with quercetin (QC, flavonoid) in lipid polymer hybrid nanoparticles (LPNs) developed using biodegradable & biocompatible materials and prepared using a single-step nanoprecipitation technique. High stability and cellular uptake, sustained release, inherent fluorescence, of ZnPC were observed after encapsulation in the LPNs, which also showed a higher cytotoxic effect in breast carcinoma cells (MCF-7) compared to photodynamic therapy (PDT) alone. In vivo studies in tumor-bearing Sprague Dawley rats demonstrated that the LPNs were able to deliver ZnPc and QC to the tumor site with minimal systemic toxicity and increased antitumor effect. Overall, the photodynamic effect of ZnPc was synergized by QC. This strategy could be highly beneficial for cancer management in the future while nullifying the side effects of chemotherapy.

Development of a light activatable lignin nanosphere based spray coating for bioimaging and antimicrobial photodynamic therapy.

Many coating materials are commercially available to combat microbial infections. However, these coatings are difficult to synthesize, and are mostly composed of toxic chemicals. Lignin is an under-explored natural biopolymer with multifaceted potential. Lignin, with adhesive, UV resistant, and antimicrobial properties, is a suitable candidate to develop coating materials. Here we report a smart method to fabricate a sustainable nanospray coating from lignin which does not require any toxic chemicals or additives during synthesis. Initially, we have developed stable lignin nanospheres in a single step in aqueous medium, which were later utilized as a lignin nanospray (LNSR). The LNSR was characterized by dynamic light scattering, scanning electron microscopy, FTIR and other analytical techniques. This LNSR showed remarkable UV blocking, antioxidant and light-activated antimicrobial properties. Interestingly, for the first time, the LNSR demonstrated photoluminescence, making it useful for bioimaging. Moreover, singlet oxygen generation potential was observed in the LNSR, which could render it useful in phototheranostic applications (i.e. light assisted imaging and photodynamic therapy). Further, the LNSR was directly utilized to fabricate a sustainable coating. The nanospray coating exhibited maximum light-induced cell killing when applied to common microbes as detected by live-dead cell imaging. Taken together, the lignin nanospray coating developed via a direct pathway holds great promise to disinfect microbes in the presence of light.

Lignin-Bimetallic Nanoconjugate Doped pH-Responsive Hydrogels for Laser-Assisted Antimicrobial Photodynamic Therapy.

Bioinspired nano-antimicrobials stand out in terms of cost effectiveness and scalability when compared to their chemically synthesized counterparts. There is limited efficacy of current antibiotics due to their interference with the immune system as well as development of antibiotic resistance. Lignin, which is a naturally abundant polyphenol-rich biopolymer, can be utilized for the fabrication of sustainable antimicrobial materials. In the present work, development of stable nanocomposite hydrogels embedded with lignin-based photodynamic nanoconjugates has been described. This could lead to complete eradication of microbial infection upon laser exposure. For designing such hydrogels, initially photosensitizer decorated lignin-metallic and lignin-bimetallic nanoconjugates were developed utilizing simple and nontoxic methods. These photodynamic nanoconjugates were then characterized and doped into a poly(acrylic acid)-based hydrogel in order to achieve efficient pH-triggered controlled release. The nanocomposite hydrogels allowed maximum transmission of light, promoting their applicability in antimicrobial photodynamic therapy. Utilization of hydrogel helped in better retention of nanoconjugates, maintaining their antimicrobial photodynamic efficacy as validated via IC50 measurement and live-dead cell imaging. The biocompatible pH-responsive photodynamic antimicrobial hydrogels developed herein could be potentially applicable in controlled drug delivery through the construction of wound dressings, as well as for developing antifungal, antibacterial, or antiviral nanocoatings.

Paclitaxel-encapsulated core-shell nanoparticle of cetyl alcohol for active targeted delivery through oral route.

Aim: Paclitaxel (PTX) has no clinically available oral formulations. Cetyl alcohol is metabolized by alcohol dehydrogenase and aldehyde dehydrogenase that are overexpressed in cancer cells. So, PTX-encapsulated core-shell nanoparticle of cetyl alcohol (PaxSLN) could target the cancer cells through oral route. Materials & methods: PaxSLN was synthesized using microemulsion template. Efficiency of PaxSLN was evaluated by ALDEFLUOR™, multicellular tumor spheroid formation inhibition assays and CT26 colorectal carcinoma animal model. Pharmacokinetics and biodistribution studies were done in Sprague Dawley rats. Results: PTX was encapsulated at the core of approximately 78 nm PaxSLN. PaxSLN targeted aldehyde dehydrogenase overexpressing cells. Its oral bioavailability was approximately 95% and chemotherapeutic efficacy was better than Taxol® and nab-PTX. Conclusion: A novel oral nanoformulation of PTX was developed.

Facile development of biodegradable polymer-based nanotheranostics: Hydrophobic photosensitizers delivery, fluorescence imaging and photodynamic therapy.

Photodynamic therapy (PDT) is reported to be a promising technique to eradicate various cancers. As most of the photosensitizers (PSs) are hydrophobic in nature, thus, the effective delivery of PSs at the targeted site is the main hurdle associated with PDT. Zinc phthalocyanine and Zinc naphthalocyanine are reported as good PSs, however, highly hydrophobic characteristics restrict their use for clinical applications. To circumvent this limitation here we developed the advanced polymer-based nano-delivery system having polyethylene glycol (PEG) coated polymeric core with ~90% PS encapsulation. The PEG coating was responsible for the stabilization of probe in the physiological environment and storage conditions. The developed theranostic probes showed efficient in vitro fluorescence and singlet oxygen quantum yields upon irradiation with 620-750 nm (30 mW/cm2) light. The clathrin-mediated endocytosis (CME) based mechanism of cellular internalization was evaluated. The fluorescence of treated MCF-7 cells showed the ability of the probes as imaging agents. Moreover, up to 65% cell inhibition showed their cytotoxic efficiency. Further, comparatively higher tumor-accumulation of PSs without significant hepato/nephro-toxicity shown in vivo experimentation using breast tumor-bearing female Sprague Dawley (SD) rats suggested the featured passive targeting ability of preparations and clinically safe to be used. The study explored the exceptional delivery system for hydrophobic PSs with commendable theranostic applications.

Self-Assembled Gold Nanoparticle-Lipid Nanocomposites for On-Demand Delivery, Tumor Accumulation, and Combined Photothermal-Photodynamic Therapy.

In this study, a distinct photoamenable nanoparticle-based drug delivery system was developed for highly efficient targeted on-demand delivery, fluorescence imaging, and therapy by incorporating zinc phthalocyanine (ZnPc) and gold nanoparticles (AuNPs) into liposomes. The hyperthermia, produced by AuNPs under LED light irradiation, enhanced the liquidity of liposomal membrane and promoted the instantaneous release of ZnPc from the carriers realizing the concept of on-demand release. In addition, the local hyperthermia also resulted in thermal damage of cancer cells along with photodynamic effect and achieved a synergetic effect of photodynamic and photothermal therapy. The developed probes showed a high breast cancer carcinoma cells (MCF-7 cell line) inhibition up to 86.7% under red light irradiation. Further, in vivo experiments suggested the high tumor accumulation as well as the antitumor effect in breast tumor-bearing female Sprague-Dawley (SD) rats. The outcomes demonstrate the capability of these probes as a novel drug delivery system to codeliver therapeutic agents with photothermal agents and will have an enormous potential for future diagnosis and therapy.

Porphyrin Functionalized Gelatin Nanoparticle-Based Biodegradable Phototheranostics: Potential Tools for Antimicrobial Photodynamic Therapy.

Photomedicine-based antimicrobial therapy has emerged as an alternative treatment for antibiotic-resistant microbial infections. Although various photosensitizers (PSs) have been reported as efficient antimicrobial agents, their efficient delivery to the specific target area requires further investigation. In the current study, development of a biodegradable phototheranostic nanoagent (PTNA) by incorporation of a PS (trans-AB-porphyrin) and gelatin nanomatrix is described. The antimicrobial efficacy of the PTNA against Gram-positive bacteria, Gram-negative bacteria, and yeast strains, along with other properties including hydrophilicity, biocompatibility, and targeting ability, is evaluated. Unlike the commonly used membrane permeabilizing chemicals that are toxic, the delivery vehicle gelatin used in this study is biocompatible and biodegradable. Here, the method offers a sustainable synthesis of gelatin-based stable formulation of nanotheranostic agents with high loading (>85%). The study revealed that the reactive oxygen species (ROS), generated in situ by the PTNAs, are primarily responsible for microbial cell death. The developed PTNAs described herein featured "nano size (<200 nm), have high fluorescence and singlet oxygen quantum yields, retain photophysical properties of PS after incorporation into the gelatin matrix, could be activated by a cost-effective light irradiation, and have efficient antimicrobial photodynamic activity." This antimicrobial photodynamic therapy using the newly synthesized phototheranostic nanoagent has manifested its competence, therapeutic modality of general acceptance, and wide-spectrum antimicrobial action.

Development of Gelatin Nanoparticle-Based Biodegradable Phototheranostic Agents: Advanced System to Treat Infectious Diseases.

Rose bengal (RB)-conjugated and -entrapped gelatin nanoparticle (GNP)-based biodegradable nanophototheranostic (Bd-NPT) agents have been developed for the efficient antimicrobial photodynamic therapy. The study reveals that the use of gelatin nanoparticles could bypass the chemicals such as potassium iodide, EDTA, calcium chloride and polymyxin nonapeptide for the penetration of drug into the cell membrane to achieve antimicrobial activity. We demonstrated that the singlet oxygen generated by the biodegradable gelatin nanoparticles (BdGNPs) could damage the microbial cell membrane and the cell dies. The key features of the successive development of this work include the environmentally benign amidation of RB with GNPs, which was so far unexplored, and the entrapment of RB into the gelatin nanoparticles (GNP). The RB-GNP exhibited potent and broad-spectrum antimicrobial activity and could be useful in treating multi-drug-resistant microbial infections.

Esterase-Mediated Highly Fluorescent Gold Nanoclusters and Their Use in Ultrasensitive Detection of Mercury: Synthetic and Mechanistic Aspects.

The fast, accurate, and ultrasensitive detection of toxic mercury in real water samples is still challenging without the use of expensive sophisticated instruments. Herein, highly fluorescent gold nanoclusters (AuNCs) were synthesized using a newer protein templet, esterase (EST). The EST-AuNCs consisted of ∼25 Au atoms in the nanocluster having ∼2 nm size. EST-AuNCs were found to be highly stable in aqueous buffer with a wide range of pH (pH 4-12) and were also stable in powdered form. The fluorescence quantum yield of EST-AuNCs in deionized water was 6.2% which had increased to 7.8% upon the addition of 1 M NaCl (an increase of 23%). The EST-AuNCs selectively sense the toxic Hg2+ ions with higher sensitivity (limit of detection; 0.88 nM) with the linear range 1-30 nM. The test strips for rapid sensing of Hg2+ in real water samples were developed on the polymeric surface. The validation of sensing ability of EST-AuNCs suggested 94-98% recovery with linearity. Moreover, because of the widely reported applications of EST, the developed EST-AuNCs could also be used for another sensing, catalytic, and biomedical applications.

Bioinspired Nanotheranostic Agents: Synthesis, Surface Functionalization, and Antioxidant Potential.

Bioinspired synthesis of nanomaterials is highly advantageous as a natural and cost-effective resource. Development of noble metal nanotheranostic agents was achieved through bioinspired synthetic routes. These biosynthesized nanoparticles were characterized by various analytical techniques including absorption spectroscopy, FTIR and electron microscopy (SEM and TEM). A large number of medicinal plants were screened, among which Potentilla fulgens (PF, vajradanti) and Camellia sinensis (CS, green tea) were found to produce nanomaterials with higher yields. Plant (PF and CS) mediated metallic nanoparticles had added advantage of metal reduction and simultaneous phytochemical capping over chemically synthesized procedures, which require multiple reagents. Antioxidant potential of the nanomaterials was determined by in vitro antioxidant assays confirming substantial antioxidant properties, which was due to the presence of phytochemicals on the nanoparticle surface. Flavonoids and catechins on the nanomaterial surface served as the supplier of hydroxyl groups for further derivatization. The surface of the nanoparticles was engineered by conjugating imaging and therapeutic moieties, resulting in the formation of theranostic nanoagents. The multimodal agents were characterized and the extent of drug loading was determined to validate the efficacy of those nanoconjugates. These bioinspired multimodal nanoprobes can serve as essential diagnostic and therapeutic tools in ongoing biomedical research.