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L‐ and D‐ form oligo(lactic acid)s (OLLA and ODLA) grafted α‐cellulose (OLLA‐g‐cellulose and ODLA‐g‐cellulose) were prepared by the graft polycondensation reaction in C6H5CH3 medium at 130°C and 380 mm of mercury pressure. Para‐toluene sulphonic acid (5 wt% of oligo(lactic acid)) was used as a catalyst whereas potassium persulfate (0.01 wt% of oligo(lactic acid)) was used as a co‐catalyst in the graft polycondensation reaction. OLLA and ODLA with a degree of polymerization (DP) 6–7 used in polycondensation reaction were also prepared by ring‐opening polymerization of L‐ and D‐lactides at 140°C for 10 h with stannous octoate (C16H30O4Sn) as a motivator, L, and D monomer of lactic acids as co‐motivators. FTIR analysis proved the bonding of OLLA and ODLA onto the α‐cellulose surface. The thermal properties of poly(L‐lactic) acid (PLLA) composites were explored by thermal analysis (TG, DTA, and DTG). Degradation, melting, and maximum weight loss temperature of the composites were increased with the increase of grafted cellulose up to 10% and then decreased. TG and DTA results showed that the incorporation of grafted α‐cellulose (grafted cellulose) can improve the thermal properties of PLLA composites. Highlights Synthesis of oligo(lactic acid)s from L‐ and D‐lactides by ring‐opening polymerization reactions. α‐cellulose extraction and graft modification with oligo(lactic acid)s. Preparation of grafted α‐cellulose composite with PLLA matrix. Evaluation of thermal properties of the grafted α‐cellulose‐reinforced composites. Grafting of cellulose with L‐ and D‐ oligo(lactic acid)s, preparation of PLLA/grafted cellulose composites and their thermal characteristics evaluations.

Oligo(L-lactic acid) (OLLA) was synthesized by ring opening polymerization of L-lactides using stannous octoate (0.03 wt% of lactide). While this served as the initiator, L-lactic acids were the co-initiators at 140 °C for 10 h, wherein L-lactic acids were prepared by hydrolytic degradation of L-lactides at 100 °C for 1 h. The molecular weight or degree of polymerization was controlled with monomer/co-initiator ratio (mol/mol). α-cellulose and microcrystalline cellulose (MCC) were extracted from jute fiber by subsequent treatment with sodium chlorite (Na2ClO2), NaOH and H2SO4. Grafting of OLLA onto α-cellulose and MCC in toluene was carried out using para-toluene sulphonic acid as a catalyst and potassium persulphate (KPS) as an initiator at 130 °C under 380 mm (Hg) pressure for 3, 6, 9, 12, 15, and 18 h. New properties of α-cellulose and MCC were observed due to the successful grafting onto α-cellulose and MCC. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were conducted in order to confirm grafting of OLLA onto cellulose and MCC. The FTIR analysis results showed there are some new characteristic absorption peaks appeared (1728 to 1732 cm−1) in the spectrum, which confirmed the grafting of OLLA onto α-cellulose and MCC was successful. SEM images of α-cellulose and MCC before and after grafting revealed significant changes in surface morphology. Grafting of MCC could be more effective for further application in comparison to α-cellulose.

Main-chain chiral quaternary ammonium polymers were successfully synthesized by the quaternization polymerization of cinchonidine dimer with dihalides. The polymerization occurred smoothly under optimized conditions to give novel type of main-chain chiral quaternary ammonium polymers. The catalytic activity of the polymeric chiral organocatalysts was investigated on the asymmetric benzylation of N-(diphenylmethylidene)glycine tert-butyl ester.

Uptake drug transporters play a significant role in the pharmacokinetic of drugs within the brain, facilitating their entry into the central nervous system (CNS). Understanding brain drug disposition is always challenging, especially with respect to preclinical to clinical translation. These transporters are members of the solute carrier (SLC) superfamily, which includes organic anion transporter polypeptides (OATPs), organic anion transporters (OATs), organic cation transporters (OCTs), and amino acid transporters. In this systematic review, we provide an overview of the current knowledge of uptake drug transporters in the brain and their contribution to drug disposition. Here, we also assemble currently available proteomics-based expression levels of uptake transporters in the human brain and their application in translational drug development. Proteomics data suggest that in association with efflux transporters, uptake drug transporters present at the BBB play a significant role in brain drug disposition. It is noteworthy that a significant level of species differences in uptake drug transporters activity exists, and this may contribute toward a disconnect in inter-species scaling. Taken together, uptake drug transporters at the BBB could play a significant role in pharmacokinetics (PK) and pharmacodynamics (PD). Continuous research is crucial for advancing our understanding of active uptake across the BBB.

A simple technique is presented to fabricate stable and reproducible plasmonic substrates using chicken eggshell as bio-templates, an otherwise everyday waste material. The 3-dimensional (3D) submicron features on the outer shell (OS), inner shell (IS), and shell membrane (SM) regions are sputter coated with gold and characterized for surface-enhanced Raman scattering (SERS) performance with respect to coating thickness, enhancement factor (EF), hot-spots distribution, and reproducibility. The OS and IS substrates have similar EF (2.6 × 106 and 1.8 × 106, respectively), while the SM provides smaller EF (1.5 × 105) due to its larger characteristic feature size. The variability from them (calculated as relative standard deviation, %RSD) are less than 7, 15, and 9 for the OS, IS, and SM substrates, respectively. Due to the larger EF and better signal reproducibility, the OS region is used for label-free sensing and identification of Escherichia coli and Bacillus subtilis bacteria as an example of the potential SERS applications. It is demonstrated that the detection limit could reach the level of single bacterial cells. The OS and IS regions are also used as templates to fabricate 3D flexible SERS substrates using polydimethylsiloxane and characterized. The simple, low-cost, and green route of fabricating plasmonic substrates represents an innovative alternative approach without the needs for nanofabrication facilities. Coupled with hyperspectral Raman imaging, high-throughput bio-sensing can be carried out at the single pathogen level.

A total of 70 scenarios with 100 subjects were simulated and estimated 100 times applying one compartment PK model with first-order absorption and sigmoid Emax model using SSE (Stochastic simulation and estimation) of PSN (Perl-speaks-NONMEM) and first order conditional estimation with interaction (FOCE-I) method in NONMEM (version 7.2).The bias and precision of the parameter estimates in each scenario were assessed using relative bias and relative root mean square error.

Plasmonic nanostructures are known to concentrate incident light to their surfaces by collective electron oscillation, a.k.a., localized surface plasmon resonance (LSPR). Plasmonic hot-spot refers to locations where electromagnetic fields are particularly enhanced relative to the incident field. Traditional plasmonic nanomaterials are 1D (e.g., colloidal nanoparticles) or 2D (lithographically patterned nanostructure arrays) in nature, which typically result in sparse field concentration patterns. To improve efficiency and better utilization of hot-spots, 3D plasmonic nanoarchitectures are desired, where abundant hot-spots are formed in a 3D volumetric fashion, a feature drastically departing from traditional nanostructures. In this dissertation, two novel 3D plasmonic nanostructures are reported. The first one is NPG nanoparticle, a disk shaped nanostructure with 3D pore-ligament bi-continuous network. NPG disks are made by the low-cost nanosphere lithography (NSL) technique, which is capable of wafer scale production. NPG disks possess larger surface area and high density internal plasmonic hot-spots, which are absent in its bulk counterparts. Due to these unique properties, NPG disks can be potentially used in various surface enhanced Raman spectroscopy (SERS), surface enhanced fluorescence (SEF), and photothermal based applications. To optimize the performance of NPG disks in various applications and understand its plasmonics better, two different modeling techniques, Bruggeman effective medium theory (B-EMT) model and Nanoporous (NP) model, are introduced and evaluated against the experimental data obtained by an electron beam lithography (EBL) compatible fabrication technique for NPG disks. The EBL method can provide large area 2D patterns of randomly distributed nanodisks with flexible interdisk (center to center) distance. Such flexibility is essential to obtain quasi-single NPG disk response, which typically peaks in the near infrared (NIR) spectrum beyond 1 ?m, from ensemble measurements by common UV/VIS/NIR spectrometers instead of a specialized NIR spectroscopic microscope. After successful fabrication and modeling, the plasmon enhanced catalysis application of NPG disks is reported in details. The effectiveness of NPG disks in various applications depends on its LSPR peak position. Hence, optimization of an application might require the fine tuning of the peak position. A novel laser based rapid thermal annealing technique is reported to fine tune the LSPR peak position of NPG disks. The second 3D plasmonic nanostructure, reported in this dissertation, is based on the chicken egg shell, a day-to-day waste material. The 3-dimensional (3D) submicron features on the outer shell (OS), inner shell (IS), and shell membrane (SM) regions are sputter coated with gold found to have excellent SERS performance. Moreover, the outer shell substrate is found to be capable of detecting single bacterial cell. This facile way of fabricating 3D plasmonic substrates can facilitate the adoption of 3D plasmonic substrates by researchers in less fortunate countries.

In this paper, a highly sensitive graphene-based multiple-layer (BK7/Au/PtSe2/Graphene) coated surface plasmon resonance (SPR) biosensor is proposed for the rapid detection of the novel Coronavirus (COVID-19). The proposed sensor was modeled on the basis of the total internal reflection (TIR) technique for real-time detection of ligand-analyte immobilization in the sensing region. The refractive index (RI) of the sensing region is changed due to the interaction of different concentrations of the ligand-analyte, thus impacting surface plasmon polaritons (SPPs) excitation of the multi-layer sensor interface. The performance of the proposed sensor was numerically investigated by using the transfer matrix method (TMM) and the finite-difference time-domain (FDTD) method. The proposed SPR biosensor provides fast and accurate early-stage diagnosis of the COVID-19 virus, which is crucial in limiting the spread of the pandemic. In addition, the performance of the proposed sensor was investigated numerically with different ligand-analytes: (i) the monoclonal antibodies (mAbs) as ligand and the COVID-19 virus spike receptor-binding domain (RBD) as analyte, (ii) the virus spike RBD as ligand and the virus anti-spike protein (IgM, IgG) as analyte and (iii) the specific probe as ligand and the COVID-19 virus single-standard ribonucleic acid (RNA) as analyte. After the investigation, the sensitivity of the proposed sensor was found to provide 183.33°/refractive index unit (RIU) in SPR angle (θSPR) and 833.33THz/RIU in SPR frequency (SPRF) for detection of the COVID-19 virus spike RBD; the sensitivity obtained 153.85°/RIU in SPR angle and 726.50THz/RIU in SPRF for detection of the anti-spike protein, and finally, the sensitivity obtained 140.35°/RIU in SPR angle and 500THz/RIU in SPRF for detection of viral RNA. It was observed that whole virus spike RBD detection sensitivity is higher than that of the other two detection processes. Highly sensitive two-dimensional (2D) materials were used to achieve significant enhancement in the Goos-Hänchen (GH) shift detection sensitivity and plasmonic properties of the conventional SPR sensor. The proposed sensor successfully senses the COVID-19 virus and offers additional (1 + 0.55) × L times sensitivity owing to the added graphene layers. Besides, the performance of the proposed sensor was analyzed based on detection accuracy (DA), the figure of merit (FOM), signal-noise ratio (SNR), and quality factor (QF). Based on its performance analysis, it is expected that the proposed sensor may reduce lengthy procedures, false positive results, and clinical costs, compared to traditional sensors. The performance of the proposed sensor model was checked using the TMM algorithm and validated by the FDTD technique.