Detection and identification of amino acids and proteins using their intrinsic fluorescence in the visible light spectrum

The detection and identification of biomolecules are essential in the modern era of medical diagnostics. Several approaches have been established, but they have significant limitations such as laborious and time-consuming sample preparation, analysis, and the need to use external probes which provide adequate but not desired levels of accuracy and sensitivity. Herein, we have explored successfully a non-invasive technique to detect and identifybiomolecules such as amino acids and proteins by utilizing their intrinsic fluorescence. The developed confocal microscopy method revealed high and photostable emission counts of these biomolecules including amino acids (tryptophan, phenylalanine, tyrosine, proline, histidine, cysteine, aspartic acid, asparagine, isoleucine, lysine, glutamic acid, arginine) and proteins (HSA, BSA) when they are excited with a green laser. The fluorescence lifetime of the samples enabled the identification and distinction of known and blind samples of biomolecules from each other. The developed optical technique is straightforward, non-destructive and does not require laborious labeling to identify specific proteins, and may serve as the basis for the development of a device that would quickly and accurately identify proteins at an amino acid level. Therefore, this approach would open an avenue for precise detection in imaging and at the same time increases our understanding of chemical dynamics at the molecular level.

Amino Acid-Coated Zeolitic Imidazolate Framework for Delivery of Genetic Material in Prostate Cancer Cell

Metal-organic frameworks (MOFs) are currently under progressive development as a tool for non-viral biomolecule delivery. Biomolecules such as proteins, lipids, carbohydrates, and nucleic acids can be encapsulated in MOFs for therapeutic purposes. The favorable physicochemical properties of MOFs make them an attractive choice for delivering a wide range of biomolecules including nucleic acids. Herein, a green fluorescence protein (GFP)-expressing plasmid DNA (pDNA) is used as a representative of a biomolecule to encapsulate within a Zn-based metal-organic framework (MOF) called a zeolitic imidazolate framework (ZIF). The synthesized biocomposites are coated with positively charged amino acids (AA) to understand the effect of surface functionalization on the delivery of pDNA to prostate cancer (PC-3) cells. FTIR and zeta potential confirm the successful preparation of positively charged amino acid-functionalized derivatives of pDNA@ZIF (i.e., pDNA@ZIF_AA). Moreover, XRD and SEM data show that the functionalized derivates retain the pristine crystallinity and morphology of pDNA@ZIF. The coated biocomposites provide enhanced uptake of genetic material by PC-3 human prostate cancer cells. The AA-modulated fine-tuning of the surface charge of biocomposites results in better interaction with the cell membrane and enhances cellular uptake. These results suggest that pDNA@ZIF_AA can be a promising alternative tool for non-viral gene delivery.

Targeting telomerase utilizing zeolitic imidazole frameworks as non-viral gene delivery agents across different cancer cell types

Telomerase, a ribonucleoprotein coded by the hTERT gene, plays an important role in cellular immortalization and carcinogenesis. hTERT is a suitable target for cancer therapeutics as its activity is highly upregulated in most of cancer cells but absent in normal somatic cells. Here, by employing the two Metal-Organic Frameworks (MOFs), viz. ZIF-C and ZIF-8, based biomineralization we encapsulate Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 plasmid system that targets hTERT gene (CrhTERT) in cancer cells. When comparing the two biocomposites, ZIF-C shows the better loading capacity and cell viability. The loaded plasmid in ZIF-C is highly protected against enzymatic degradation. CrhTERT@ZIF-C is efficiently endocytosed by cancer cells and the subcellular release of CrhTERT leads to telomerase knockdown. The resultant inhibition of hTERT expression decreases cellular proliferation and causing cancer cell death. Furthermore, hTERT knockdown shows a significant reduction in tumour metastasis and alters protein expression. Collectively we show the high potential of ZIF-C-based biocomposites as a promising general tool for gene therapy of different types of cancers.

Synthesis and biological evaluation of 1-phenyl-4,6-dihydrobenzo[b]pyrazolo[3,4-d]azepin-5(1H)-one/thiones as anticancer agents

Cancer is associated with uncontrolled cell proliferation invading adjoining tissues and organs. Despite the availability of several chemotherapeutic agents, the constant search for newer approaches and drugs is necessitated owing to the ever-growing challenge of resistance. Over the years, DNA has emerged as an important druggable therapeutic drug due to its role in critical cellular processes such as cell division and maintenance. Further, evading apoptosis stands out as a hallmark of cancer. Hence, designing new compounds that would target DNA and induce apoptosis plays an important role in cancer therapy. In the current work, we carried out the synthesis and anticancer evaluation of 1-aryl-4,6-dihydrobenzo[b]pyrazolo[3,4-d]azepin-5(1H)-ones/thiones (26 compounds) against selected human cancer cell lines. Among these, compounds 8ae, 8ad, 8cf, 10ad and Kenpaullone have shown good inhibitory properties against HeLa cells (IC₅₀ < 2 µM) with good selectivity over the non-cancerous human embryonic kidney (Hek293T) cells. In cell cycle analysis, the compounds 8ad and 8cf have exhibited G₂/M cell cycle arrest in HeLa cells. In addition, the compounds 8ad and 8cf induced apoptosis in a dose-dependent manner in the Annexin-V FITC staining assay. The DAPI staining clearly demonstrated the condensed and fragmented nuclei in 8ad, 8cf, 8ae and Kenpaullone-treated HeLa cells. In addition, these compounds strongly suppressed the healing after 48 h in in vitro cell migration assay. The DNA binding experiments indicated that compounds 8ae, 8cf, and 8ad as well as Kenpaullone interact with double-stranded DNA by binding in grooves which may interrupt the DNA replication and kill fast-growing cells. Molecular docking studies revealed the binding pose of 8ad and Kenpaullone at HT1 binding pocket of double-stranded DNA. Compounds 8ad and 8cf demonstrated moderate topo II inhibition which could be a possible reason for their anticancer properties. Compounds 8ad and 8cf may cause the topo II and DNA covalent complex, which leads to the inhibition of DNA replication and transcription. This eventually increases the DNA damage in cells and promotes cell apoptosis. With the above interesting biological profile, the new 1-aryl-2,6-dihydrobenzo[b]pyrazolo[3,4-d]azepin-5(4H)-one/thione derivatives have emerged as promising leads for the discovery of new anticancer agents.

Targeted in vitro gene silencing of E2 and nsP1 genes of chikungunya virus by biocompatible zeolitic imidazolate framework

Chikungunya fever caused by the mosquito-transmitted chikungunya virus (CHIKV) is a major public health concern in tropical, sub-tropical and temperate climatic regions. The lack of any licensed vaccine or antiviral agents against CHIKV warrants the development of effective antiviral therapies. Small interfering RNA (siRNA) mediated gene silencing of CHIKV structural and non-structural genes serves as a potential antiviral strategy. The therapeutic efficiency of siRNA can be improved by using an efficient delivery system. Metal-organic framework biocomposits have demonstrated an exceptional capability in protecting and efficiently delivering nucleic acids into cells. In the present study, carbonated ZIF called ZIF-C has been utilized to deliver siRNAs targeted against E2 and nsP1 genes of CHIKV to achieve a reduction in viral replication and infectivity. Cellular transfection studies of E2 and nsP1 genes targeting free siRNAs and ZIF-C encapsulated siRNAs in CHIKV infected Vero CCL-81 cells were performed. Our results reveal a significant reduction of infectious virus titre, viral RNA levels and percent of infected cells in cultures transfected with ZIF-C encapsulated siRNA compared to cells transfected with free siRNA. The results suggest that delivery of siRNA through ZIF-C enhances the antiviral activity of CHIKV E2 and nsP1 genes directed siRNAs.

Microwave-assisted rapid synthesis of spirooxindole-pyrrolizidine analogues and their activity as anti-amyloidogenic agents

A library of Sox-pyrrolizidines was rapidly prepared by microwave-assisted, one-pot, three-component, 1,3-dipolar cycloaddition of azomethine ylides from l-proline and isatin, with various β-nitrostyrenes. Nitro-Sox compounds, 4b, 4d and 4e inhibit HEWL amyloid fibril formation by ThT studies with percentages of fluorescence intensity of 55.4, 42.9 and 40.3%, respectively. Further studies with MTT assay, Raman spectroscopy, TEM and molecular docking supported these promising candidates for activity against amyloid misfolding, a phenomenon leading to Alzheimer's disease pathology.

Nanodiamond-chitosan functionalized hernia mesh for biocompatibility and antimicrobial activity

Polypropylene (PP) mesh is most commonly used for the treatment of hernia and pelvic floor construction. However, some of the patients have a few complications after surgery due to the rejection or infection of the implanted meshes. The poor biocompatibility of PP mesh, low wettability results in poor cell attachment/proliferation and restricts the loading of antibacterial agent, leading to a slow healing process and high risk of infection after surgery. Here in this study, a new technique has been employed to develop a novel antimicrobial and biocompatible PP mesh modified with bioactive chitosan and functionalized nanodiamond (FND) for infection inhibition and acceleration of the healing process. An oxygen plasma treatment PP mesh was used then chitosan was strongly attached to the surface of the PP fibers. Subsequently, FND as an antibacterial agent was loaded into the chitosan modified PP fiber to provide desired antibacterial functions. The meshes were characterised with XRD, FTIR, SEM, EDX, water contact angle, confocal, and optical microscopy. The modified PP mesh with chitosan and FND showed a significant increase in its hydrophilicity and L929 fibroblast cell attachment. Furthermore, the modified mesh exhibited great antibacterial efficiency against Escherichia coli. Therefore, the newly developed technique to modify PP mesh could be a promising technique to generate a biocompatible PP mesh to accelerate the healing process and reduce the risk of infection after surgery.

ZIF-C for targeted RNA interference and CRISPR/Cas9 based gene editing in prostate cancer

Metal–organic-frameworks for gene therapy in prostate cancer – ZIF-C based delivery of RNA interference and CRISPR/Cas9 causes host gene expression knockdown. Coating with a green tea phytochemical enhances uptake and increases cancer cytotoxicity.

Polyethylene glycolated PAMAM dendrimers-Efavirenz conjugates

Aim:

The preparation of novel PEGylated PAMAM (poly-amidoamine) dendrimers for delivery of anti-HIV drug Efavirenz is reported.

Method and Materials:

About 5.0 G PAMAM dendrimers are prepared by ethylene diamine core via Michael addition by divergent method. PEGylation is done by polyethylene glycol 600 using epichlorhydrin as linker. PEGylated 5.0 G PAMAM dendrimers loaded with Efavirenz (EFV) are evaluated for FTIR, DSC, SEM, drug release, and stability studies.

Results and Conclusion:

From the results it is proved that this method is less time consuming, inexpensive, and reproducible. Drug-release studies indicate, PEGylated 5.0 G PAMAM-EFV dendrimers have shown prolonged drug-release property.