Detection of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) using a fully automated system with a nano-scale engineered biomagnetite

Biotin-functionalized nanoparticles: an overview of recent trends in cancer detection

Electrochemical bio-sensing is a potent and efficient method for converting various biological recognition events into voltage, current, and impedance electrical signals. Biochemical sensors are now a common part of medical applications, such as detecting blood glucose levels, detecting food pathogens, and detecting specific cancers. As an exciting feature, bio-affinity couples, such as proteins with aptamers, ligands, paired nucleotides, and antibodies with antigens, are commonly used as bio-sensitive elements in electrochemical biosensors. Biotin-avidin interactions have been utilized for various purposes in recent years, such as targeting drugs, diagnosing clinically, labeling immunologically, biotechnology, biomedical engineering, and separating or purifying biomolecular compounds. The interaction between biotin and avidin is widely regarded as one of the most robust and reliable noncovalent interactions due to its high bi-affinity and ability to remain selective and accurate under various reaction conditions and bio-molecular attachments. More recently, there have been numerous attempts to develop electrochemical sensors to sense circulating cancer cells and the measurement of intracellular levels of protein thiols, formaldehyde, vitamin-targeted polymers, huwentoxin-I, anti-human antibodies, and a variety of tumor markers (including alpha-fetoprotein, epidermal growth factor receptor, prostate-specific Ag, carcinoembryonic Ag, cancer antigen 125, cancer antigen 15-3, etc.). Still, the non-specific binding of biotin to endogenous biotin-binding proteins present in biological samples can result in false-positive signals and hinder the accurate detection of cancer biomarkers. This review summarizes various categories of biotin-functional nanoparticles designed to detect such biomarkers and highlights some challenges in using them as diagnostic tools.

Bio-Nanocarriers for Lung Cancer Management: Befriending the Barriers

Lung cancer is a complex thoracic malignancy developing consequential to aberrations in a myriad of molecular and biomolecular signaling pathways. It is one of the most lethal forms of cancers accounting to almost 1.8 million new annual incidences, bearing overall mortality to incidence ratio of 0.87. The dismal prognostic scenario at advanced stages of the disease and metastatic/resistant tumor cell populations stresses the requisite of advanced translational interdisciplinary interventions such as bionanotechnology. This review article deliberates insights and apprehensions on the recent prologue of nanobioengineering and bionanotechnology as an approach for the clinical management of lung cancer. The role of nanobioengineered (bio-nano) tools like bio-nanocarriers and nanobiodevices in secondary prophylaxis, diagnosis, therapeutics, and theranostics for lung cancer management has been discussed. Bioengineered, bioinspired, and biomimetic bio-nanotools of considerate translational value have been reviewed. Perspectives on existent oncostrategies, their critical comparison with bio-nanocarriers, and issues hampering their clinical bench side to bed transformation have also been summarized.

A Guideline for Effectively Synthesizing and Characterizing Magnetic Nanoparticles for Advancing Nanobiotechnology: A Review

The remarkable multimodal functionalities of magnetic nanoparticles, conferred by their size and morphology, are very important in resolving challenges slowing the progression of nanobiotechnology. The rapid and revolutionary expansion of magnetic nanoparticles in nanobiotechnology, especially in nanomedicine and therapeutics, demands an overview of the current state of the art for synthesizing and characterizing magnetic nanoparticles. In this review, we explain the synthesis routes for tailoring the size, morphology, composition, and magnetic properties of the magnetic nanoparticles. The pros and cons of the most popularly used characterization techniques for determining the aforementioned parameters, with particular focus on nanomedicine and biosensing applications, are discussed. Moreover, we provide numerous biomedical applications and highlight their challenges and requirements that must be met using the magnetic nanoparticles to achieve the most effective outcomes. Finally, we conclude this review by providing an insight towards resolving the persisting challenges and the future directions. This review should be an excellent source of information for beginners in this field who are looking for a groundbreaking start but they have been overwhelmed by the volume of literature.

Tuning properties of biomimetic magnetic nanoparticles by combining magnetosome associated proteins

The role of magnetosome associated proteins on the in vitro synthesis of magnetite nanoparticles has gained interest, both to obtain a better understanding of the magnetosome biomineralization process and to be able to produce novel magnetosome-like biomimetic nanoparticles. Up to now, only one recombinant protein has been used at the time to in vitro form biomimetic magnetite precipitates, being that a scenario far enough from what probably occurs in the magnetosome. In the present study, both Mms6 and MamC from Magnetococcus marinus MC-1 have been used to in vitro form biomimetic magnetites. Our results show that MamC and Mms6 have different, but complementary, effects on in vitro magnetite nucleation and growth. MamC seems to control the kinetics of magnetite nucleation while Mms6 seems to preferably control the kinetics for crystal growth. Our results from the present study also indicate that it is possible to combine both proteins to tune the properties of the resulting biomimetic magnetites. In particular, by changing the relative ratio of these proteins, better faceted and/or larger magnetite crystals with, consequently, different magnetic moment per particle could be obtained. This study provides with tools to obtain new biomimetic nanoparticles with a potential utility for biotechnological applications.

Learning from magnetotactic bacteria: A review on the synthesis of biomimetic nanoparticles mediated by magnetosome-associated proteins

Much interest has gained the biomineralization process carried out by magnetotactic bacteria. These bacteria are ubiquitous in natural environments and share the ability to passively align along the magnetic field lines and actively swim along them. This ability is due to their magnetosome chain, each magnetosome consisting on a magnetic crystal enveloped by a lipid bilayer membrane to which very unique proteins are associated. Magnetotactic bacteria exquisitely control magnetosome formation, making the magnetosomes the ideal magnetic nanoparticle of potential use in many technological applications. The difficulty to scale up magnetosome production has triggered the research on the in vitro production of biomimetic (magnetosome-like) magnetite nanoparticles. In this context, magnetosome proteins are being used to mediate such in vitro magnetite precipitation experiments. The present work reviews the knowledgement on the magnetosome proteins thought to have a role on the in vivo formation of magnetite crystals in the magnetosome, and the recombinant magnetosome proteins used in vitro to form biomimetic magnetite. It also summarizes the data provided in the literature on the biomimetic magnetite nanoparticles obtained from those in vitro experiments.

Magnetotactic bacteria: nanodrivers of the future

Magnetotactic bacteria (MTB) represent a heterogeneous group of Gram-negative aquatic prokaryotes with a broad range of morphological types, including vibrioid, coccoid, rod and spirillum. MTBs possess the virtuosity to passively align and actively swim along the magnetic field. Magnetosomes are the trademark nano-ranged intracellular structures of MTB, which comprise magnetic iron-bearing inorganic crystals enveloped by an organic membrane, and are dedicated organelles for their magnetotactic lifestyle. Magnetosomes endue high and even dispersion in aqueous solutions compared with artificial magnetites, claiming them as paragon nanomaterials. MTB and magnetosomes offer high technological potential in modern science, technology and medicines. This review focuses on the applicability of MTB and magnetosomes in various areas of modern benefits.

Evaluation of current methods to detect the mutations of epidermal growth factor receptor in non-small cell lung cancer patients

Many different methods were developed to detect commonly known mutations and to screen new mutations of the epidermal growth factor receptor in non-small cell lung cancer patients. Some of these methods are so sensitive as to be able to detect even one epidermal growth factor receptor mutant tumor cell among up to 1000–2000 normal cells. We have considered current methods chronologically reported to detect mutations in epidermal growth factor receptor in patients with non-small cell lung cancer. We also gave a short preview of their significance for routine clinical works. A Pub Med literature search was performed in order to demonstrate what methods are mostly used in mutation detection and to show their distribution through the last 10 years.

Formation of magnetite by bacteria and its application

Magnetic particles offer high technological potential since they can be conveniently collected with an external magnetic field. Magnetotactic bacteria synthesize bacterial magnetic particles (BacMPs) with well-controlled size and morphology. BacMPs are individually covered with thin organic membrane, which confers high and even dispersion in aqueous solutions compared with artificial magnetites, making them ideal biotechnological materials. Recent molecular studies including genome sequence, mutagenesis, gene expression and proteome analyses indicated a number of genes and proteins which play important roles for BacMP biomineralization. Some of the genes and proteins identified from these studies have allowed us to express functional proteins efficiently onto BacMPs, through genetic engineering, permitting the preservation of the protein activity, leading to a simple preparation of functional protein-magnetic particle complexes. They were applicable to high-sensitivity immunoassay, drug screening and cell separation. Furthermore, fully automated single nucleotide polymorphism discrimination and DNA recovery systems have been developed to use these functionalized BacMPs. The nano-sized fine magnetic particles offer vast potential in new nano-techniques.

Novel method for evaluation of chemicals based on ligand-dependent recruitment of GFP labeled coactivator to estrogen receptor displayed on bacterial magnetic particles

We established a novel method to evaluate endocrine disrupting chemicals (EDCs) by assembling the estrogen receptor-ligand binding domain (ERLBD) and GFP labeled coactivator on magnetic nanoparticles. EDC can promote or inhibit coactivator recruitment to the ligand-ERLBD complex. ERLBD was displayed on the surface of nano-sized bacterial magnetic particles (BacMPs) produced by the magnetic bacterium, Magnetospirillum magneticum AMB-1. Our method resulted in 38 molecules of ERLBD molecules on a BacMPs with diameter of 75nm. Furthermore, ligand-dependent recruitment assays of GFP labeled coactivator to ERLBD-BacMPs was performed by measuring the fluorescence intensity. 17Beta-estradiol (E2), estriol, diethylstilbestrol, zeralenone (full agonist), octylphenol (partial agonist) and ICI 182,780 (antagonist) were evaluated by this method. Full agonists tested showed increased fluorescence with increasing agonist concentration. Octylphenol had lower fluorescence intensity than E2. ICI 182,780 did not produce any fluorescence. The method developed in this study can evaluate the estrogenic potential of chemicals by discriminating whether they are an ER full agonist, partial agonist, or antagonist. Finally, this method is amenable adaptation into a high throughput format by using automated magnetic separation.

Sensitive detection of EGFR mutations using a competitive probe to suppress background in the SMart Amplification Process

In a previous study, a single nucleotide polymorphism (SNP) diagnostic system named the SMart Amplification Process version 2 (SMAP 2) was reported, which enabled rapid gene diagnostics from crude samples such as whole blood. The asymmetric primer design and use of Taq MutS were reported as innovative background suppression technologies employed by SMAP 2, but Taq MutS is known to display differential affinities for various mismatch combinations, and hence may not be entirely effective for all possible applications. To address this issue we developed another approach using a competitive probe (CP) to enhance background suppression technology instead of Taq MutS. CP is a 3'-end aminated oligonucleotide that competes with 3'-end of a discrimination primer or the self-priming elongation site on intermediate product 2 (IM2) for non-target sequences, such as the alternative allele. The preferred hybridization kinetics for the full-match CP on the non-target sequence results in effective background suppression in SMAP 2 assays. By using a CP, we demonstrated the sensitive detection of EGFR gene mutations in purified genomic DNA from mixed cell populations. The CP approach is another tool enhancing the effectiveness and versatility of SMAP 2 assays, expanding its potential applications, and reinforcing its position as a highly effective technology for molecular diagnostics.

Rapid detection of epidermal growth factor receptor mutations in lung cancer by the SMart-Amplification Process

PURPOSE

A positive response to gefitinib in non-small cell lung cancer (NSCLC) has been correlated to mutations in epidermal growth factor receptor (EGFR) gene. Previous reports have been based mainly on diagnostic screening by sequencing. However, sequencing is a time-consuming and complicated procedure, not suitable for routine clinical use.

EXPERIMENTAL DESIGN

We have developed rapid, simple, and sensitive mutation detection assays based on the SMart Amplification Process (SMAP) and applied it for analyzing EGFR gene mutations in clinical samples. By using SMAP, we can detect mutations within 30 min including sample preparation. To validate the assay system for potential use in clinical diagnostics, we examined 45 NSCLC patients for EGFR mutations using sequencing and SMAP.

RESULTS

The outcomes of the SMAP assay perfectly matched the sequencing results, except in one case where SMAP was able to identify a mutation that was not detected by sequencing. We also evaluated the sensitivity and specificity of SMAP in mutation detection for EGFR. In a serial dilution study, SMAP was able to find a mutation in a sample containing only 0.1% of the mutant allele in a mixture of wild-type genomic DNA. We also could show amplification of mutated DNA with only 30 copies per reaction.

CONCLUSIONS

The SMAP method offers higher sensitivity and specificity than alternative technologies, while eliminating the need for sequencing to identify mutations in the EGFR gene of NSCLC. It provides a robust and point-of-care accessible approach for a rapid identification of most patients likely to respond to gefitinib.