Metallic Nanocarriers for Therapeutic Peptides: Emerging Solutions Addressing the Delivery Challenges in Brain Ailments

Peptides and proteins have recently emerged as efficient therapeutic alternatives to conventional therapies. Although they emerged a few decades back, extensive exploration of various ailments or disorders began recently. The drawbacks of current chemotherapies and irradiation treatments, such as drug resistance and damage to healthy tissues, have enabled the rise of peptides in the quest for better prospects. The chemical tunability and smaller size make them easy to design selectively for target tissues. Other remarkable properties include antifungal, antiviral, anti-inflammatory, protection from hemorrhage stroke, and as therapeutic agents for gastric disorders and Alzheimer and Parkinson diseases. Despite these unmatched properties, their practical applicability is often hindered due to their weak susceptibility to enzymatic digestion, serum degradation, liver metabolism, kidney clearance, and immunogenic reactions. Several methods are adapted to increase the half-life of peptides, such as chemical modifications, fusing with Fc fragment, change in amino acid composition, and carrier-based delivery. Among these, nanocarrier-mediated encapsulation not only increases the half-life of the peptides in vivo but also aids in the targeted delivery. Despite its structural complexity, they also efficiently deliver therapeutic molecules across the blood-brain barrier. Here, in this review, we tried to emphasize the possible potentiality of metallic nanoparticles to be used as an efficient peptide delivery system against brain tumors and neurodegenerative disorders. SIGNIFICANCE STATEMENT: In this review, we have emphasized the various therapeutic applications of peptides/proteins, including antimicrobial, anticancer, anti-inflammatory, and neurodegenerative diseases. We also focused on these peptides' challenges under physiological conditions after administration. We highlighted the importance and potentiality of metallic nanocarriers in the ability to cross the blood-brain barrier, increasing the stability and half-life of peptides, their efficiency in targeting the delivery, and their diagnostic applications.

Evaluation of physicochemical properties of graphene oxide-decellularized pericardium biohybrid scaffold

The decellularized pericardium has been widely used in cardiac tissue engineering, whereas its clinical applications are limited due to weak mechanical performance, high collagen exposure, and being prone to microbial contamination. In this study, a biohybrid scaffold of the decellularized caprine pericardium (DCP) and graphene oxide (GO) was fabricated by an immersion coating technique. The antimicrobial activity of GO was evaluated against Escherichia coli and showed minimum inhibitory concentration at 125 μg/mL and minimum bactericidal concentration at 250 μg/mL. The presence of GO on the surface of the biohybrid GO-DCP was confirmed through SEM analysis. The existence of glycosaminoglycan, elastin, and collagen in the DCP and GO-DCP was inferred from the FTIR spectra. The biocompatibility of GO-DCP was studied by seeding valvular interstitial cells, and the results show GO coating supports cell adhesion on the serous and fibrous sides of the DCP. Further, the biomechanical response of DCP is unaltered by the presence of GO. In conclusion, GO enhances the biological performance of decellularized pericardium, which can be used in cardiac tissue engineering applications.

Biodegradable AZ91 magnesium alloy/sirolimus/poly D, L-lactic-co-glycolic acid-based substrate for cardiovascular device application

Biodegradable drug-eluting stents (DESs) are gaining importance owing to their attractive features, such as complete drug release to the target site. Magnesium (Mg) alloys are promising materials for future biodegradable DESs. However, there are few explorations using biodegradable Mg for cardiovascular stent application. In this present study, sirolimus-loaded poly D, L-lactic-co-glycolic acid (PLGA)-coated/ sirolimus-fixed/AZ91 Mg alloy-based substrate was developed via a layer-by-layer approach for cardiovascular stent application. The AZ91 Mg alloy was prepared through the squeeze casting technique. The casted AZ91 Mg alloy (Mg) was alkali-treated to provide macroporous networks to hold the sirolimus and PLGA layers. The systematic characterization was investigated via electrochemical, optical, physicochemical, and in-vitro biological characteristics. The presence of the Mg17 Al12 phase in the Mg sample was found in the x-ray diffraction system (XRD) spectrum which influences the corrosion behavior of the developed substrate. The alkali treatment increases the substrate's hydrophilicity which was confirmed through static contact angle measurement. The anti-corrosion characteristic of casted-AZ91 Mg alloy (Mg) was slightly less than the sirolimus-loaded PLGA-coated alkali-treated AZ91 Mg alloy (Mg/Na/S/P) substrate. However, dissolution rates for both substrates were found to be controlled at cell culture conditions. Radiographic densities of AZ91 Mg alloy substrates (Mg, Mg/Na, and Mg/Na/S/P) were measured to be 0.795 ± 0.015, 0.742 ± 0.01, and 0.712 ± 0.017, respectively. The star-shaped structure of 12% sirolimus/PLGA ensures the bioavailability of the drugs. Sirolimus release kinetic was fitted up to 80% with the "Higuchi model" for Mg samples, whereas Mg/Na/S/P showed 45% fitting with a zero-order mechanism. The Mg/Na/S/P substrate showed a 70% antithrombotic effect compared to control. Further, alkali treatment enhances the antibacterial characteristic of AZ91 Mg alloy. Also, the alkali-treated sirolimus-loaded substrates (Mg/Na/S and Mg/Na/S/P) inhibit the valvular interstitial cell's growth significantly in in-vitro. Hence, the results imply that sirolimus-loaded PLGA-coated AZ91 Mg alloy-based substrate can be a potential candidate for cardiovascular stent application.

Exploring the bioactivity of reduced graphene oxide and TiO2 nanocomposite for the regenerative medicinal applications

Millions of people globally suffer from issues related to chronic wounds due to infection, burn, obesity, and diabetes. Nanocomposite with antibacterial and anti-inflammatory properties is a promising material to promote wound healing. This investigation primarily aims to synthesize reduced graphene oxide and titanium dioxide (rGO@TiO2) nanocomposite for wound healing applications. The rGO@TiO2 nanocomposite was synthesized by the one-step hydrothermal technique, and the physicochemical characterization of synthesized nanocomposite was performed by X-ray diffraction, Fourier transforms infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, and dynamic light scattering. Further, the nanocomposite antibacterial, cytotoxicity, and wound-healing properties were analyzed by disc diffusion method, MTT assay, and in vitro scratch assay, respectively. Based on the TEM images, the average particle size of TiO2 nanoparticles was around 9.26 ± 1.83 nm. The characteristics peak of Ti-O-Ti bonds was observed between 500 and 850 cm-1 in the Fourier transforms infrared spectrum. The Raman spectrum of graphene oxide (GO) was obtained for bands D and G at 1354 cm-1 and at 1593 cm-1, respectively. This GO peak intensity was reduced in rGO, revealing the oxygen functional group reduction. Moreover, the rGO@TiO2 nanocomposite exhibited dose-dependent antibacterial properties against the positive and negative bacterium. The cytotoxicity for 5-100 µg/mL of rGO@TiO2 nanocomposite was above the half-maximal inhibitory concentration value. The in vitro scratch assay for rGO@TiO2 indicates that the nanocomposite promotes cell proliferation and migration. The nanocomposite recovered the wound within 48 h. The rGO@TiO2 nanocomposite shows potential materials for wound healing applications.

Multiplex polymerase chain reaction for the detection of high-risk-human papillomavirus types in formalin-fixed paraffin-embedded cervical tissues

Detecting high-risk-human papillomavirus (HPV) types has become an integral part of the cervical cancer screening programmes. This study aimed to develop a multiplex polymerase chain reaction (PCR) for identification of HPV types 16 and 18 along with the beta globin gene in formalin-fixed and paraffin-embedded cervical biopsy specimens. A total of 59 samples from patients with cervical abnormalities were tested. HPV 16 positivity was 50% in cervical cancers and 52.9% in cervical intraepithelial neoplasia. Our multiplex PCR protocol can be used as a simple and cost-effective tool for high-risk-HPV detection in cervical cancer screening programmes.

Evaluation of shear bond strength of zirconia bonded to dentin after various surface treatments of zirconia

Establishing a reliable bond of resin cement to zirconia based materials has been a major limitation against zirconia restoration.

PURPOSE OF STUDY

This study evaluated the shear bond strength of zirconia bonded to dentin specimens using a self etch dual cure resin cement after various surface treatments of zirconia. Twenty zirconia rods (3 × 2.5 mm) were prepared from zirconia blocks and assigned into 5 groups for the following surface treatments. (1) Group I: Control (C) no treatment (2) Group II: airborne-particle abrasion (APA), (3) Group III: hydrofluoric acid etching (HF), (4) Group IV: hydrofluoric acid etching followed by silanation (HF/S), and (5) Group V: application of zirconia primer (Z). Dentin Specimens were prepared from extracted molars stored in 0.5% chloramine-T. Zirconia rods were bonded to dentin using resin cement (Multilink Speed), then light polymerized. The specimens tested for failure were tested using the notched shear bond test method in a universal loading apparatus. One way ANOVA followed by Tukey HSD for cell means were used to analyze the data (=0.05). The highest values were obtained with group V (Z) (8.66 MPa) followed by group II (APA) (6.71 MPa), and group IV (HF/S) (4.41 MPa). The least values were obtained for group III (HF) (3.88 MPa) with no significant difference (P value 0.53) between group III (HF) (3.88 MPa) and group I (C) (3.70 MPa). Among the surface treatments employed in this study zirconia primer application is a practical procedure to improved bond strength of zirconia to resin cement followed by Airborne Particle Abrasion with 50 μm Al2O3 particles.