Muhammad Mujahid

Characterization and application of roxithromycin loaded cyclodextrin based nanoparticles for treatment of multidrug resistant bacteria.

An outbreak of infections with a high mortality rate caused by multidrug resistant (MDR) bacteria is one of the biggest health challenges globally. A class IV drug, roxithromycin (ROX), has poor solubility. In this study, ROX was first encapsulated in the cavity of each of the β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD). Then, each of the resulting βCD-ROX inclusion complex and HPβCD-ROX inclusion complex were separately loaded into poly-(lactic-co-glycolic acid) (PLGA) to synthesize βCD-ROX/PLGA and HPβCD-ROX/PLGA nanoparticles (NPs). Blank and ROX loaded PLGA (ROX-PLGA) NPs were also prepared. The loading efficiency of ROX is comparatively high for HPβCD-ROX/PLGA NPs in comparison to the βCD-ROX/PLGA NPs and ROX-PLGA NPs. All designed formulations showed significant (P<0.0001) antibacterial activity against the selected MDR bacterial strains. In a nutshell, this study demonstrated a great therapeutic potential of the above-mentioned delivery systems for treatment of MDR bacteria.

Multi Band Gap Cu(In,Ga)(S,Se)2 Thin Films Deposited by Spray Pyrolysis for High Performance Solar Cell Devices

The performance of copper indium gallium disulfoselenide (CIGSSe) solar cells strongly depends on the band bap of absorbing layer of CIGSSe. The device performance can be improved by fabricating multi band gap layer of CIGSSe. However, the fabrication of multi band gap CIGSSe using non-vacuum techniques is challenging. In this study, we fabricated solar cell devices which consisted of multi band gap Cu (In,Ga)(S,Se)2 thin films. The CIGS thin films were prepared by the spray-pyrolysis of aqueous precursor solutions of gallium (gallium chloride; GaCl3), copper (indium chloride; CuCl2), indium (indium chloride; InCl3), and Sulphur (thiourea; (SC(NH2)2) sources on Mo-coated glass substrate. The as-sprayed thin films were then selenized at 500 °C for 10 minutes.After selenization, CIGS films were transformed to Cu (In,Ga)(S,Se)2 (CIGSSe). The CIGS films with different composition were deposited again on top of selenized CIGSSe films and selenization process was repeated, hence multi band gap CIGSSe films were fabricated. The Chemical bath deposition (CBD) process was used to deposit cadmium sulphide (CdS) buffer layer. The solar cell fabricated with the device configuration of glass/Mo/CIGSSe/CdS/i-ZnO/AZO showed a power conversion efficiency of 6.51%.

Investigation on physical properties of solution-processed inorganic metal-oxides based charge extraction layers for 3G hybrid solar cells

Charge extraction layers, which include the hole extraction layer (HEL) and the electron extraction layer (EEL), are an essential component of a hybrid solar cell. In this work, charge extraction layers for hybrid solar cells have been fabricated from low-temperature solution-phase synthesis techniques by utilizing inexpensive and non-toxic inorganic metal-oxide semiconductors. Subsequently, the films have been optimized in terms of their various physical properties via microscopy based characterization techniques. Nanoparticles of zinc oxide and molybdenum trioxide have been synthesized by wet chemistry precipitation route at temperatures below 100C. X-ray Diffraction (XRD) analysis confirms high purity and hexagonal structure of the as-synthesized nanoparticles. Charge extraction layers were deposited by spincoating the colloidal suspension and initial study of film quality via optical microscopy indicated positive results for zinc oxide film. Nanoparticles of molybdenum trioxide, as opposed to zinc oxide, form larger aggregates during film deposition, hence resulting in poorer film quality in terms of coverage, adhesion and stability. Therefore, an alternate fabrication route is proposed for molybdenum trioxide film as the HEL to replace the conventionally used acidic and hygroscopic PEDOT:PSS polymer. For the EEL, the result of varying concentrations of colloidal dispersion on the surface morphology of the zinc oxide film on a nanoscale regime is analyzed through SEM studies. Finally, these optimized charge extraction layers are suitable for use in hybrid solar cells based on photoactive layer comprising of organic semiconductor P3HT.