Sadhana Talele

Drug Delivery by Electroporation: Review

Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Most common routes of administration include the preferred non-invasive peroral (through the mouth), topical (skin), transmucosal (nasal, buccal/sublingual, vaginal, ocular and rectal) and inhalation routes. Current effort in the area of drug delivery include the development of targeted delivery in which the drug is only active in the target area of the body (for example, in cancerous tissues) and sustained release formulations in which the drug is released over a period of time in a controlled manner from a formulation. This is achieved by combining electroporation with the input of drugs at a location. This paper reviews the process of electroporation and then further discusses the electrochemotherapy, one of the most upcoming application of electroporation in biotechnology.

An Optimised Six-Wavelength Model for Predicting Kiwifruit Dry Matter:

Optimised wavelength selection is important to the development of new types of inexpensive and portable near infrared instruments that might be used on fruit in orchards. The use of discrete bandwidth devices, such as light-emitting diodes, requires preselection of a small number of discrete wavelengths. In this work, a kiwifruit data set consisting of 834 absorbance spectra and corresponding fruit dry-matter measurements, an important maturity indicator for kiwifruit, has been subjected to an exhaustive wavelength search to build optimal multiple linear regression models of up to seven wavelengths. Using a standard partial least-squares model as a benchmark, a six-wavelength model has been identified as an optimum, predicting kiwifruit dry matter with r2 of 0.88 and root mean square error of prediction (RMSEP) of 1.22%. The sensitivity of the model to shifts in the key wavelengths was also evaluated, revealing that a 1 nm offset or a 0.25 nm random noise component would be enough to increase the RMSEP by around 0.04% in actual dry matter value or 3% in relative percentage terms.

Implementation of the supercapacitor-assisted surge absorber (SCASA) technique in a practical surge protector

Their combination of large continuous energy ratings and very large time constants allows supercapacitors to be used in surge protection circuits. This fact, supported by recent research publications and laboratory tests, has assisted the authors to propose a new surge protection circuit topology known as the supercapacitor-assisted surge absorber (SCASA). This technique utilizes a multi-winding transformer, common surge protector devices such as metal oxide Varistors (MOV) and/or semiconductor types combined with a supercapacitor sub-circuit to absorb part of the surge energy usually expected to dissipate within the MOV or the semiconductor. The paper presents design details and test results for a differential mode surge protector based on the SCASA technique where the test device was subjected to lightning-type surges defined in international standards for Class-A and Class B type protectors. The performance of a prototype based on Class-B waveforms of up to 6.6 kV surges generated from a lightning surge simulator are discussed in the paper. Its performance is compared with two commercially available surge protectors.

Laser-induced breakdown spectroscopy analysis of sodium in pelletised pasture samples

Sodium concentration in plants inhibit shoot and root growth. Traditional wet-chemical methods of determining elemental concentrations require pre-treatment and leave unwanted by-products. Laser-induced breakdown spectroscopy is a technique that needs very little pre-treatment and produces no secondary waste. Laser-induced breakdown spectroscopy is used in this work to determine sodium concentrations in dried pasture samples. Temperature correction on the gathered spectra was attempted using Boltzmann and Saha-Boltzmann plots. These methods failed to deliver satisfactory results. Different combinations of internal reference standards were used on the Na I 818.326 nm line which resulted in an improved correlation with sodium concentration. Partial least squares regression was used on the gathered spectra to find emission lines that vary with the sodium concentration. Calcium, sodium, potassium and an argon line demonstrated high predictor weights. The Na I 818.326 nm, Na I 819.482 nm, K I 693.876 nm and K I 691.108 nm lines exhibited large dependence on sodium concentration. Building a calibration curve of sodium to potassium emission line intensity versus sodium to potassium concentration in the samples produced a correlation of R2 = 0.918 and an error in prediction of 0.0254.

Modelling Control of Pore Number and Radii Distribution in Single-Cell Electroporation

Electroporation EP, in which external electric field pulses create transient pores in a cell membrane, is an important technique for delivery of genes and drugs into the cell. To enable a useful level of entry of genes into cells, the pores should have sufficiently large radii, and remain open long enough without causing membrane rupture. A numerical model for a single spherical cell electroporated by application of direct and/or alternating external electric field pulses has been developed. The model is used to indicate the actual number of pores and their radii distribution developed in response to various electric field pulses, as function of time and position on the cell surface. This study briefly describes the model briefly which is then used to investigate the ability to control the number and distribution of pore radii by choice of electric field parameters. We believe this would be one of the first papers to investigate the ability to CONTROL the number and distribution (range) of pore radii (as opposed to other papers that merely report the pore number and range with varying pulse parameters.

Interferometric surface plasmon resonance based on low-cost grating substrates

Surface plasmon resonance (SPR) has been used for some time in chemical and biological sensors. Some of the schemes for exciting surface plasmons include prisms and gratings. Grating-based optical SPR sensors have been demonstrated, which use light intensity variations at resonance or wavelength interrogation. Recently, a gold grating made from a commercial recordable compact disk was used for excitation of surface plasmons and SPR imaging. In this paper, we present a new grating configuration that combines the benefits of multi-angle interrogation with interferometric measurement techniques. This gives array sensing capability over a wide refractive index range. The set-up is based on the gold grating of commercially available recordable compact disks, which are mass produced by injection-moulding, resulting in low cost and disposable grating substrates. The potential of using this system for large sample number analysis is demonstrated.

Technological Development in Therapeutic Applications of Alternating Electric Fields: Review

A number of bacteria, virus and other unhealthy cells need to be killed for getting rid of them. For more than a century antibiotics have been effectively used for killing bacterial pathogens and chemical drugs against the cancer cells. However, there are bacteria and cancer cells that are drug resistant. This may have to be overcome by other stronger drugs, higher dosage. These can have detrimental side effects. Other non drug methods to aid the effect of these drugs have always been in research. Electrochemotherapy, a method of using electric fields along with the drug to be used topically has been one of the successful approaches. One of the most recent methods of Tumor Treating Frequencies (TTF) for a brain cancer has been FDA approved. This article details the use of TTF. The article also details some other latest research where alternating fields are used as antibacterial agents.

Wine Maturation Using High Electric Field

Wine maturation can take a long time and consumes storage space which can be a drawback while considering commercial aspect of wine making. In the past scientists have carried out experiments on maturing wine quickly using ultrasounds or gamma radiations. This study reports about maturing wine with high electric field at different frequencies applied for a short time duration. The electric field intensity and the frequency of the field along with the exposure time of wine to this field seem to be important parameters that could affect the the treated wine. Results obtained are encouraging and have a potential for commercial interest.

Modelling Single Cell Electroporation with Bipolar Pulse: Simulating Dependance of Electroporated Fractional Pore Area on the Bipolar Field Frequency

Electroporation EP, in which external electric field pulses create transient pores in a cell membrane, is an important technique for delivery of DNA and drugs into the cell. To enable entry of DNA into cells, the pores should have sufficiently large radii, remain open long enough for the DNA chain to enter the cell, and should not cause membrane rupture. A numerical model for a single spherical cell electroporated by application of direct and/or alternating external electric field pulses has been developed. The model is used to calculate the transmembrane potential, the number of pores and the the fraction of area occupied by the pores (fractional pore area FPA) in response to the various electric field pulses. Presented here are simulation results used to compare the extent of electroporation (fractional pore area FPA) in response to eletric field pulses of different frequencies in a range of extracellular conductivity for two cell raii. It is also observed that a 1 MHz bipolar sinusoidal applied electric field pulse reduces the relative difference in fractional pore area between the two cell sizes compared to a 100 kHz pulse.