Bradford protein assay

About: Bradford protein assay is a research topic. Over the lifetime, 635 publications have been published within this topic receiving 239107 citations.

Degradation of earthworm extracts prepared by wet superfine grinding in simulated gastrointestinal environment

Abstract: This is to report the study of degradation of earthworm extracts prepared by wet superfine grinding in simulated gastrointestinal environment. Enzymatic reactions were terminated by adjusting the solution pH or using membrane bioreactor principle. Earthworm protein concentration change was detected by Bradford method, the degraded state of protein was described with SDS-PAGE technology, and the degraded state of small molecule substances was detected by HPLC. The results showed that earthworm protein degraded completely in artificial gastric juice. High molecular weight protein degraded greatly in artificial intestinal fluid, while low molecular weight protein was not significantly degraded. Small molecular substances degradation did not degrade in artificial gastric juice, while they degraded obviously in artificial intestinal fluid, there is even new small molecule substance appeared. Finally it is concluded that the substance that having therapeutic effects in vivo may be some degraded peptide, amino acid and stable small molecules existed in artificial intestinal fluid.

Absorbance amplification using chromophore-nanoplasmon coupling for ultrasensitive protein quantification.

Abstract: A plasmonic nanoscale Lycurgus cup array (nanoLCA), via near-field interaction with chromophores in commercial colorimetric biochemical assays, can drastically enhance assay sensitivity by over 2 orders of magnitude. A 96-microwell plate modified by placing the plasmonic nanoLCA on the well-bottom was used with the commercial Bradford protein quantification assay. Plasmons on the nanoLCA serve as an energy donor to matched resonance chromophores, and the near-field plasmonic energy coupling effect results in an increase in absorbance value at the plasmonic resonance wavelength. Even with a 5.1-fold reduced sample volume, a limit of detection enhancement factor of 200 is accomplished using the nanoLCA compared to using the conventional Bradford assay without plasmon aid. The nanoLCA-microplate sensing platform is readily scalable to 384- or 1536-microwell plates, which further reduces the sensing volume and boosts detection throughput with the enhanced sensitivity.

Opto-Microfluidic Integration of the Bradford Protein Assay in Lithium Niobate Lab-on-a-Chip

Abstract: This paper deals with the quantification of proteins by implementing the Bradford protein assay method in a portable opto-microfluidic platform for protein concentrations lower than 1.4 mg/mL. Absorbance is measured by way of optical waveguides integrated to a cross-junction microfluidic circuit on a single lithium niobate substrate. A new protocol is proposed to perform the protein quantification based on the high correlation of the light absorbance at 595 nm, as commonly used in the Bradford method, with the one achieved at 633 nm with a cheap commercially available diode laser. This protocol demonstrates the possibility to quantify proteins by using nL volumes, 1000 times less than the standard technique such as paper-analytical devices. Moreover, it shows a limit of quantification of at least 0.12 mg/mL, which is four times lower than the last literature, as well as a better accuracy (98%). The protein quantification is obtained either by using one single microfluidic droplet as well by performing statistical analysis over ensembles of several thousands of droplets in less than 1 min. The proposed methodology presents the further advantage that the protein solutions can be reused for other investigations and the same pertains to the opto-microfluidic platform.

Effect of chitosan on protein content in the medium culture of osteoblasts exposed to oxidative stress

Abstract: Chitosan is a derivative of chitin which has potential for use in bone regeneration and has been reported can stimulate bone formation. Oxidative stress as one cause of bone damage, was found increased in osteoporosis, periodontitis and arthritis. One of the species oxygen reactive (ROS), hydrogen peroxide, has been reported can inhibit osteoblast pro-liferation. This study was aimed to investigate the effect of various chitosan concentrations on protein content in the culture medium of human osteoblast-like cell line, MG 63, which was exposed to hydrogen peroxide. MG 63 cells were exposed to various chitosan concentrations (% w/v) 0.1, 0.2, 0.4, and 1.6%. Culture cells without chitosan were used as a control. Cells were growth with α-MEM medium (37oC, 5% CO 2 ) until they became confluent, then they were exposed to hydrogen peroxide for 4 hours. The protein content in the culture medium was measured by using Bradford protein assay at 655 nm wavelength. The result showed that hydrogen peroxide decreased protein concentration in the medium culture compared with group without hydrogen peroxide. Treatment group with chitosan concentration 0.4% and 1.6% exhibited a significant increasing of protein concentration in osteoblast culture medium compared with control. In conclusion, in osteoblast culture medium chitosan can inhibit the decreasing of total protein concentration which was caused by oxidative stress. Key words: osteoblast, hydrogen peroxide, chitosan, protein concentration