Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer's Research

We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aβ) in a microfluidic environment. The Aβ was separated from the cells and characterized using the gradual dissolution of Aβ as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aβ under specific dielectrophoretic parameters. Further, Aβ in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aβ fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aβ to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aβ-related colloidal microfluidic research and could be applied to Alzheimer’s research in the future.

Dielectrophoretic deformation of breast cancer cells for lab on a chip applications

This paper presents the development and experimental analysis of a curved microelectrode platform for the DEP deformation of breast cancer cells (MDA-MB-231). The platform is composed of arrays of curved DEP microelectrodes which are patterned onto a glass slide and samples containing MDA-MB-231 cells are pipetted onto the platform's surface. Finite element method is utilised to characterise the electric field gradient and DEP field. The performance of the system is assessed with MDA-MB-231 cells in a low conductivity 1% DMEM suspending medium. We applied sinusoidal wave AC potential at peak to peak voltages of 2, 5, and 10 V_pp at both 10 kHz and 50 MHz. We observed cell blebbing and cell shrinkage and analyzed the percentage of shrinkage of the cells. The experiments demonstrated higher percentage of cell shrinkage when cells are exposed to higher frequency and peak to peak voltage electric field.

Dielectrophoresis-based microfluidic platforms for cancer diagnostics

The recent advancement of dielectrophoresis (DEP)-enabled microfluidic platforms is opening new opportunities for potential use in cancer disease diagnostics. DEP is advantageous because of its specificity, low cost, small sample volume requirement, and tuneable property for microfluidic platforms. These intrinsic advantages have made it especially suitable for developing microfluidic cancer diagnostic platforms. This review focuses on a comprehensive analysis of the recent developments of DEP enabled microfluidic platforms sorted according to the target cancer cell. Each study is critically analyzed, and the features of each platform, the performance, added functionality for clinical use, and the types of samples, used are discussed. We address the novelty of the techniques, strategies, and design configuration used in improving on existing technologies or previous studies. A summary of comparing the developmental extent of each study is made, and we conclude with a treatment of future trends and a brief summary.

Active bioparticle manipulation in microfluidic systems

The motion of bioparticles in a microfluidic environment can be actively controlled using several tuneable mechanisms, including hydrodynamic, electrophoresis, dielectrophoresis, magnetophoresis, acoustophoresis, thermophoresis and optical forces.

A time series based sequence prediction algorithm to detect activities of daily living in smart home

OBJECTIVES

The goal of smart homes is to create an intelligent environment adapting the inhabitants need and assisting the person who needs special care and safety in their daily life. This can be reached by collecting the ADL (activities of daily living) data and further analysis within existing computing elements. In this research, a very recent algorithm named sequence prediction via enhanced episode discovery (SPEED) is modified and in order to improve accuracy time component is included.

METHODS

The modified SPEED or M-SPEED is a sequence prediction algorithm, which modified the previous SPEED algorithm by using time duration of appliance's ON-OFF states to decide the next state. M-SPEED discovered periodic episodes of inhabitant behavior, trained it with learned episodes, and made decisions based on the obtained knowledge.

RESULTS

The results showed that M-SPEED achieves 96.8% prediction accuracy, which is better than other time prediction algorithms like PUBS, ALZ with temporal rules and the previous SPEED.

CONCLUSIONS

Since human behavior shows natural temporal patterns, duration times can be used to predict future events more accurately. This inhabitant activity prediction system will certainly improve the smart homes by ensuring safety and better care for elderly and handicapped people.

Validity and reliability of the Arabic short version of the child oral health-related quality of life questionnaire (CPQ 11-14) in Medina, Saudi Arabia

The Arabic version of the Child Perception Questionnaire for assessing oral health-related quality of life in 11-14 year olds (CPQ 11-14) has been validated previously. This study tested the validity and reliability of a short version of the Arabic CPQ 11-14 in the general population of Medina, Saudi Arabia. A total of 268 schoolchildren completed the questionnaire and were examined to determine the prevalence of caries and malocclusion. The mean total score was 8.53 (SD 8.18), and 7% of children scored zero. There was a significant association between malocclusion and oral symptoms and between DMFT score and functional limitations. The test-retest reliability (0.78) and Cronbach alpha (0.82) were excellent. The construct validity was acceptable for oral health (ρ = 0.37) and overall well-being (ρ = 0.40). The Arabic version of the short form CPQ 11-14 was reliable and valid for this general population of children.

Acute renal failure owing to paraphenylene diamine hair dye poisoning in Sudanese children

INTRODUCTION

Paraphenylene diamine (PPD) has traditionally been used as a dark-coloured hair dye. In Sudan, it is used by women to colour their hair and as a body dye when added to henna (Lawasonia alba). Accidental or deliberate ingestion causes severe systemic toxicity. Although a wide variety of complications has been described, there are few reports in children.

AIM

To describe the clinical features, management and outcome of PPD intoxication in Sudanese children.

METHODS

Data for a 3-year period (2006-2008) were extracted from the medical records of the Paediatric Nephrology Unit, Soba University Hospital. Information included the circumstances of poisoning, gender, age distribution, clinical presentation, biochemical findings and outcome.

RESULTS

Over the 3-year period, 17 children (16 female) were admitted to the Paediatric Nephrology Unit with PPD intoxication. Mean age was 13.8 yrs (range 2-18). Thirteen (76.4%) had attempted suicide, three (17.6%) were poisoned as a result of attempted murder and one poisoning (5.8%) was accidental. Eight children (47%) required tracheostomy for severe angioneurotic oedema. Of 12 (71%) who developed acute renal failure (ARF), nine required dialysis and three were managed conservatively. Two children (12%) died and the other 15 recovered with normal renal function.

CONCLUSION

PPD intoxication is a life-threatening condition with significant morbidity and mortality in children. Clinical manifestations and outcome are similar to those in adults. Mortality can be reduced by early recognition, prompt referral and aggressive supportive treatment.