Arginine-α, β-dehydrophenylalanine Dipeptide Nanoparticles for pH-Responsive Drug Delivery

Purpose

Nanoparticles (NPs) exhibiting responsiveness towards pH variations in organs, tissue microenvironments and cellular compartments can significantly add on to the drug delivery potential. Here, we have developed NPs from an amphipathic dipeptide, Arginine-α, β-dehydrophenylalanine (RΔF), and tried to explore their pH responsive drug delivery potential in various cancer cells.

Methods

RΔF-NPs were architectured by harnessing the process of molecular self-assembly followed by the assessment of effect of pH on NPs morphology using zetasizer, SEM and CD. FTIR and PXRD analysis of the dipeptide and doxorubicin (Dox) were carried out for compatibility assessment followed by encapsulation of Dox in RΔF-NPs. RΔF-Dox-NPs were evaluated for pH dependent release as well as for in-vitro cellular internalization and efficacy in cancer cells.

Results

RΔF self-assembled to form monodispersed particles at pH 7. SEM analysis revealed a loss of overall particle morphology along with particle aggregation at highly acidic and basic pH respectively. The NPs demonstrated a slow and sustained release behaviour at pH 7 (97.64?±?4.71% after 36 h) in comparison to pH 2 (90.27?±?1.45% after 8 h) and pH 10 (96.39?±?3.87% after 12 h). In-vitro efficacy studies carried-out in various cancer cells revealed that RΔF-Dox-NPs exhibited higher efficacy with 1.65, 1.95 and 13.34 fold lower IC₅₀ values in comparison to Dox in C6, HCT-116 and AGS cell lines.

Conclusions

RΔF-Dox-NPs with higher drug release at acidic pH, enhanced internalization in cancer cells along with higher cytotoxic potential can act as effective pH responsive drug delivery systems.

     

Low Concentration of a Dioxin (2, 3, 7, 8 TCDD) Affects the Glycosidases and Acid Phosphatase Activity in Mice Hepatocytes

Present communication reports the effects of environmentally available, low doses of tetra chloro di benzo-p-dioxin (2,3,7,8 TCDD) to lysosomal enzymes in mice liver. The study tests the hypothesis, in vivo exposure of low dose TCDD provokes dose and duration dependent toxic effects to key lysosomal enzymes and thereby causes cellular apoptotic changes. Three groups of female Swiss albino mice were subjected to two doses of TCDD (0.004 mg/kg bw/d, 0.04 mg/kg bw/d) for 2, 4 and 6 days of exposure durations. The results indicated significant exposure duration dependent effects of TCDD in mice liver cells. The results suggested that TCDD possibly induced an increase in intracellular ions or ROS which in turn altered different physiological activities by affecting different metabolic pathway of the liver cells. The altered functions of key lysosomal enzymes by TCDD may also evoke the process of cellular apoptosis.     

Magnitude of peripheral neuropathy in cirrhosis of liver patients from central rural India

Context:

Cirrhosis of liver is an important cause of morbidity and mortality and if associated with peripheral neuropathy (PN) it also poses a huge financial, psychological burden for the patients and their families.

Aim:

The aim of the present study was to study the magnitude of PN among subjects with cirrhosis of liver presenting to tertiary care teaching hospital in central rural India.

Settings and Design:

A cross-sectional study was performed in a tertiary care teaching hospital.

Materials and Methods:

In all patients of cirrhosis of liver irrespective of etiology, aged 15 and above, undergone clinical assessment for peripheral nervous systems damage and confirmed by nerve conduction studies.

Statistical Analysis Used:

We used chi square test to study associations. P value ≤0.05 was considered as significant. Crude odds ratios were computed to assess the strength of association between independent variables and dependent variables along with their 95% confidence intervals.

Results:

We included 207 of cirrhosis of liver patients admitted in medicine department from November 2010 through November 2013. Nearly 83% patients were male and 63.2% patients were under the age of 45 years. Common features in these patients were ascites (71%) splenomegaly (63.3%) pedal edema (61.4%) icterus (46.4%) tingling (44.9%) gastrointestinal bleeding(39.1%), ataxia (26.6%), numbness(26.6%), distal motor weakness (21.7%) and paresthesia(20.8%). Among the manifestation of peripheral nerve involvement, loss of ankle reflex was the most common feature in 51.7%, followed by loss of temperature sense 29.5%, loss of vibration sense 20.8%, loss of touch 16.4%, loss of position sense 14.5% and loss of pain in 6.3% of the patients. Peripheral neuropathy was found in 53.6% [95% CI: 46.58- 60.56] study subjects on electrophysiological study.

Conclusions:

Analysis of electrophysiological study shows that the PN is very common in study subjects with cirrhosis of liver, especially in male subjects, during the middle age group.     

Structure-Function Analyses of New SARS-CoV-2 Variants B.1.1.7, B.1.351 and B.1.1.28.1: Clinical,Diagnostic, Therapeutic and Public Health Implications

SARS-CoV-2 (Severe Acute Respiratory Syndrome-Coronavirus 2) has accumulated multiple mutations during its global circulation. Recently, three SARS-CoV-2 lineages, B.1.1.7 (501Y.V1), B.1.351 (501Y.V2) and B.1.1.28.1 (P.1), have emerged in the United Kingdom, South Africa and Brazil, respectively. Here, we have presented global viewpoint on implications of emerging SARS-CoV-2 variants based on structural–function impact of crucial mutations occurring in its spike (S), ORF8 and nucleocapsid (N) proteins. While the N501Y mutation was observed in all three lineages, the 501Y.V1 and P.1 accumulated a different set of mutations in the S protein. The missense mutational effects were predicted through a COVID-19 dedicated resource followed by atomistic molecular dynamics simulations. Current findings indicate that some mutations in the S protein might lead to higher affinity with host receptors and resistance against antibodies, but not all are due to different antibody binding (epitope) regions. Mutations may, however, result in diagnostic tests failures and possible interference with binding of newly identified anti-viral candidates against SARS-CoV-2, likely necessitating roll out of recurring “flu-like shots” annually for tackling COVID-19. The functional relevance of these mutations has been described in terms of modulation of host tropism, antibody resistance, diagnostic sensitivity and therapeutic candidates. Besides global economic losses, post-vaccine reinfections with emerging variants can have significant clinical, therapeutic and public health impacts.     

Genetic System of Artemisia maritima L.: An Overexploited Medicinal Species Under Stress

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Artemisia maritima L., a potent source of Santonin (a drug used to expel roundworms), forms isolated...     

UK National Audit of chlamydial infection management in sexual health clinics. clinic policies audit

There was a wide range of activity and chlamydial diagnoses between the 177 clinics that responded. Most (92%) clinics have nucleic acid tests for chlamydial diagnosis. Different practitioners largely share roles in providing advice to patients about partner notification, treatment adherence, safer sex advice and abstinence. Most (97%) clinics have information leaflets about chlamydia, although about 30% of clinics lack leaflets containing information about antibiotics and hormonal contraception. About two-third clinics follow the National Guideline recommended interval for providing a test of cure where this is indicated. Only 18% of clinics routinely ask patients to reattend, with 40% having a policy of no routine follow-up and 62% using telephone or text follow-up. These categories were not mutually exclusive. Most (86%) of the 146 English clinics had a local Chlamydia Screening Programme coordinator for their Primary Care Trust area, although cooperation varies, with cooperation over treatment of 70% and Programme policy of 62%.     

Dual colorimetric sensing of ascorbic acid and thyroxine using Ag–EGCG–CTAB via a DFT approach

In this work, a colorimetric approach for the detection of ascorbic acid (AA) and thyroxine (TH) was developed by synthesizing cost-effective silver nanoparticles (AgNPs) decorated with epigallocatechin gallate (EGCG) and CTAB. EGCG is the major bioactive chemical constituent that played a significant role in this study. The environment around the nanoparticle (NP) was controlled by adding CTAB surfactants. The synthesized NPs were characterized by different advanced techniques including XRD, XPS, SEM, and TEM. UV-visible spectra were thoroughly analyzed for sensing of AA and TH and the colour change of the solution can be visually monitored. The change in the localized surface plasmon resonance (LSPR) properties was used as an asset for the detection of AA and TH. A good linear relationship was obtained in both the sensing schemes with a limit of detection (LoD) of 0.67 μM and 0.33 μM for AA and TH respectively. Furthermore, the nanoparticles (NP) were implemented for real-sample analysis (pharmaceutical tablets). A cost-effective filter paper strip-based method coupled with smartphone scanning sensing was developed for the detection of AA. The interaction of AA and TH with the probe was depicted by a density functional theory (DFT) analysis. The synthesized NPs show tremendous selectivity towards AA and TH and excellent potential for practical applications.

In this work, a colorimetric approach for the detection of ascorbic acid and thyroxine was developed by synthesizing cost-effective silver nanoparticles (AgNPs) decorated with epigallocatechin gallate (EGCG) and CTAB.     

Correction: Realization of multi-configurable logic gate behaviour on fluorescence switching signalling of naphthalene diimide congeners

Correction for ‘Realization of multi-configurable logic gate behaviour on fluorescence switching signalling of naphthalene diimide congeners’ by Hridoy Jyoti Bora et al., RSC Adv., 2021, 11, 35274–35279. DOI: 10.1039/d1ra06728a.

The authors regret that there was an error in the sentence in lines 24–27 in the left column on page 35278 of the original article. The text originally read, “Mass spectrometric data Shimadzu UV-Vis spectrophotometer, UV-2600 is used to record the absorption spectra were gained from a THERMO 3000 Exactive Plus Orbitrap Mass Spectrometer”. This sentence should read, “Mass spectrometric data were gained from a THERMO 3000 Exactive Plus Orbitrap Mass Spectrometer. Shimadzu UV-Vis spectrophotometer, UV-2600 is used to record the absorption spectra”.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.