Magnetic Nanoparticles PCR Enzyme-Linked Gene Assay for Quantitative Detection of BCR/ABL Fusion Gene in Chronic Myelogenous Leukemia.

BACKGROUND: Magnetic nanoparticles (MNPs) have been widely used in medical diagnostic research. In this work, two technologies, MNPs and polymerase chain reaction (PCR), were combined to increase detection sensitivity and specificity. A novel technique based on the MNPs-PCR enzyme-linked gene assay (MELGA) was developed for detection of the BCR/ABL abnormal gene in chronic myelogenous leukemia (CML) patients. METHODS: An MNPs-labeled BCR forward primer and a biotin-labeled ABL reverse primer were used to specifically amplify the target gene. After magnetic separation, the PCR product bound to MNPs labeled with streptavidin-conjugated horseradish peroxidase was incubated with the peroxidase substrate and hydrogen peroxide to generate the colorimetric signal. RESULTS: When compared with real-time quantitative-PCR (RQ-PCR), the MELGA technique exhibited an increased sensitivity of <1 fg with high specificity for the BCR/ABL fusion gene in CML patients. In addition, MELGA colorimetric results correlated well with the number of copies obtained from RQ-PCR. CONCLUSION: This simple and cost-effective technique is suitable for monitoring CML patients during targeted therapy (tyrosine kinase inhibitors) especially in rural hospitals.

BSA Adsorption on Titanium Dioxide Nanoparticle Surfaces for Controlling Their Cellular Uptake in Skin Cells.

Nanoparticles (NPs) are continuously being developed for many applications including imaging, biomedicine, and everyday products. It is difficult to avoid contact with NPs such as titanium dioxide (TiO2) NPs, which are widely used in sunscreens. However, the safety of TiO2 NPs for skin contact and inhalation remains controversial. If NPs cannot penetrate the skin, they will be unable to circulate in the bloodstream, accumulate in the body, or cause side effects, ensuring their safety. Therefore, this study aimed to modify TiO2 NP surfaces to inhibit their uptake in skin cells. Inspired by protein corona studies, bovine serum albumin (BSA) was chosen to functionalize TiO2 NP surfaces via physical adsorption. The maximum BSA adsorption occurred at pH 5.0. The physicochemical properties (size, ζ-potential, morphology, ultraviolet (UV) absorption efficiency, and sun protection factor (SPF)) of TiO2-BSA NPs were comparable to those of TiO2 NPs, indicating that these properties did not affect cellular uptake. In the safety evaluation, TiO2 NPs and TiO2-BSA NPs exhibited high biocompatibility with skin cells and no phototoxicity after UVA and UVB irradiation. In the efficacy evaluation, both NPs possessed the same photoprotection abilities, reducing membrane damage and DNA breakage after UVA irradiation. Compared with TiO2 NPs, TiO2-BSA NPs showed substantially reduced skin penetration in Franz diffusion cells (91%) and human immortalized keratinocyte (HaCaT) cells (89%). A qualitative cellular uptake study using transmission electron microscopy and confocal laser scanning microscopy confirmed that TiO2 NPs were more abundant than TiO2-BSA NPs inside the HaCaT cells. These findings indicate that TiO2 surface functionalization with BSA inhibits cellular uptake in skin cells while maintaining safety and UV protection efficacy, which might be extended to other NP-based sunscreens.

Enhancing leptospirosis control with nanosensing technology: A critical analysis.

Leptospirosis is a serious health problem in tropical areas; thus, animals shed leptospires in the environment. Humans are accidental hosts infected through exposure to contaminating bacteria in the environment. One health strategy can be applied to protect and eliminate leptospirosis because this cooperates and coordinates activities between doctors, veterinarians, and ecologists. However, conventional methods still have limitations. Therefore, the main challenges of leptospirosis control are the high sensing of detection methods to screen and control the pathogens. Interestingly, nano sensing combined with a leptospirosis detection approach can increase the sensitivity and eliminate some limitations. This article reviews nanomaterial development for an advanced leptospirosis detection method, e.g., latex beads-based agglutination test, magnetic nanoparticles enrichment, and gold-nanoparticles-based immunochromatographic assay. Thus, nanomaterials can be functionalized with biomolecules or sensing molecules utilized in various mechanisms such as biosensors. Over the last decade, many biosensors have been developed for Leptospira spp. pathogen and others. The evolution of biosensors for leptospirosis detection was designed for high efficiency and might be an alternative tool. In addition, the high-sensing fabrications are useful for leptospires screening in very low levels, for example, soil or water from the environment.

Detection of Vibrio cholerae using the intrinsic catalytic activity of a magnetic polymeric nanoparticle.

A novel and sensitive magnetic polymeric nanoparticle (MPNP)-polymerase chain reaction-colorimetry (magneto-PCR-colorimetry) technique was developed for detection of Vibrio cholerae ( V. cholerae ). The technique involved an amplification of V. cholerae DNA on the surface of an MPNP and then employed the intrinsic catalytic activity of the MPNP to detect the target gene by colorimetry. An amino-modified forward primer was covalently labeled onto the MPNP surface which would bind to PCR product during PCR cycling. By employing the catalytic activity of the MPNP, the analysis of PCR product bound MPNP yielded a sensitivity of 10(3) CFU/mL of V. cholerae in buffer system within 4 h. The specificity and efficiency of the technique were investigated by using various bacterial DNAs in drinking and tap water.

Fabrication of Sacha Inchi Oil-Loaded Microcapsules Employing Natural-Templated Lycopodium clavatum Spores and Their Pressure-Stimuli Release Behavior.

Polymeric particles have attracted vast attention for use in various fields, especially as drug carriers and cosmetics, due to their excellent ability to protect active ingredients from the environment until reaching a target site. However, these materials are commonly produced from conventional synthetic polymers, which impose adverse effects on the environment due to their non-degradable nature, leading to waste accumulation and pollution in the ecosystem. This work aims to utilize naturally occurring Lycopodium clavatum spores to encapsulate sacha inchi oil (SIO), which contains active compounds with antioxidant activity, by applying a facile passive loading/solvent diffusion-assisted method. Sequential chemical treatments by acetone, potassium hydroxide, and phosphoric acid were employed to remove native biomolecules from the spores before encapsulation effectively. These are mild and facile processes compared to other synthetic polymeric materials. Scanning electron microscopy and Fourier-transform infrared spectroscopy revealed the clean, intact, and ready-to-use microcapsule spores. After the treatments, the structural morphology of the treated spores remained significantly unchanged compared to the untreated counterparts. With an oil/spore ratio of 0.75:1.00 (SIO@spore-0.75), high encapsulation efficiency and capacity loading values of 51.2 and 29.3%, respectively, were obtained. Using antioxidant assay (DPPH), the IC50 of SIO@spore-0.75 was 5.25 ± 3.04 mg/mL, similar to that of pure SIO (5.51 ± 0.31 mg/mL). Under pressure stimuli (1990 N/cm3, equivalent to a gentle press), a high amount of SIO was released (82%) from the microcapsules within 3 min. At an incubation time of 24 h, cytotoxicity tests showed a high cell viability of 88% at the highest concentration of the microcapsules (10 mg/mL), reflecting biocompatibility. The prepared microcapsules have a high potential for cosmetic applications, especially as functional scrub beads in facial washing products.

Sizing down and functionalizing polylactide (PLA) resin for synthesis of PLA-based polyurethanes for use in biomedical applications.

Alcoholysis is a promising approach for upcycling postconsumer polylactide (PLA) products into valuable constituents. In addition, an alcohol-acidolysis of PLA by multifunctional 2,2-bis(hydroxymethyl)propionic acid (DMPA) produces lactate oligomers with hydroxyl and carboxylic acid terminals. In this work, a process for sizing down commercial PLA resin to optimum medium-sized lactate oligomers is developed at a lower cost than a bottom-up synthesis from its monomer. The microwave-assisted reaction is conveniently conducted at 220-240 °C and pressure lower than 100 psi. The PLA resin was completely converted via alcohol-acidolysis reaction, with a product purification yield as high as 93%. The resulting products are characterized by FTIR, 2D-NMR, 1H-NMR, GPC, DSC, and XRD spectroscopy. The effects of PLA: DMPA feed ratios and the incorporation of 1,4-butanediol (BDO) on the structures, properties, and particle formability of the alcohol-acidolyzed products are examined. The products from a ratio of 12:1, which possessed optimum size and structures, are used to synthesize PLA-based polyurethane (PUD) by reacting with 1,6-diisocyanatohexane (HDI). The resulting PUD is employed in encapsulating lavender essential oil (LO). Without using any surfactant, stable LO-loaded nanoparticles are prepared due to the copolymer's self-stabilizability from its carboxylate groups. The effect of the polymer: LO feed ratio (1.25-3.75: 1) on the physicochemical properties of the resulting nanoparticles, e.g., colloidal stability (zeta potential > -60 mV), hydrodynamic size (300-500 nm), encapsulation efficiency (80-88%), and in vitro release, are investigated. The LO-loaded nanoparticles show non-toxicity to fibroblast cells, with an IC50 value higher than 2000 µg/mL. The products from this process have high potential as drug encapsulation templates in biomedical applications.

Solvent-sensitive nanoparticle-enhanced PCR assay for the detection of enterotoxigenic Escherichia coli.

Stimulus-responsive nanoparticles are among the most utilized nanoscale materials in biomedical applications. As these nanoparticles exhibit a manipulable response to a particular stimulus, such as pH, heat, and organic solvent, they are potential signalling units in diagnostic assays. This study aims to enhance the limit of detection and reduce the turnaround time of magnetic nanoparticle polymerase chain reaction (PCR) enzyme-linked gene assay (MELGA), an advanced PCR-based technique termed the solvent-sensitive nanoparticle (SSNP)-enhanced PCR assay. This technique was proposed to detect pathogenic enterotoxigenic Escherichia coli (ETEC) through applying stimulus-responsive nanoparticles. The SSNPs were elaborated with three main components, including mesoporous silica nanoparticles as a structural unit, organic dye (Nile red) as a payload, and the corresponding organic solvent-sensitive polymer shell as "gatekeeper" (poly(maleic anhydride-alt-methyl vinyl ether, PMAMVE). A suitable organic solvent capable of inducing polymer swelling and dye dissolution was investigated by considering a solubility parameter. Using ethanol, the encapsulated Nile red can diffuse out of the SSNPs faster than other solvents and reach a constant concentration within 15 min. For the PCR inhibition study, various SSNPs concentrations (10-30 µg/reaction) were mixed with the ETEC gene and PCR reagent. The results showed that the particles in this concentration range did not inhibit PCR. By comparing the efficacy of conventional PCR, MELGA, and SSNP-enhanced PCR assay, the proposed technique showed a better detection limit than that of PCR, whereas that of MELGA was the lowest. Moreover, compared to MELGA or conventional PCR, this technique provided remarkably faster results in the postamplification process.

DNA detection of chronic myelogenous leukemia by magnetic nanoparticles.

A novel tool for the detection of BCR/ABL fusion gene in chronic myelogenous leukemia (CML) was developed by a magneto-polymerase chain reaction (PCR)-enzyme linked gene technique. The forward primers covalently bound to the surface of magnetic nanoparticles allowed a convenient separation of PCR products with high sensitivity (0.5 pg ml(-1)) and high specificity using K562 cell line and CML patients. The results were obtained when the biotinylated-reverse primer bound to streptavidin-horseradish peroxidase (HRP) and hydrolysed the substrate. This novel readout system was approximately 1000-fold more sensitive than the conventional agarose gel electrophoresis. The present technique is practical and useful for following up CML patients and for providing appropriate treatment, particularly to patients in remote areas.

Smaller Is Not Always Better: Large-Size Hollow Polydopamine Particles Act as an Efficient Sun Protection Factor Booster for Sunscreens.

Ultraviolet (UV) radiation from the sun is the most harmful factor for human skin, causing sunburn, melasma, freckles, blemishes, and skin cancer. Sunscreens play a key role in blocking UV absorption on the skin. This study focused on the synthesis of hollow polydopamine (h-PDA), whose structure mimics the naturally occurring melanin in humans, for use as an active ingredient in sunscreens by means of a hard-template-based method. The reactions involve a spontaneous polymerization of a dopamine monomer in the presence of tris(hydroxymethyl)aminomethane (Tris) as a catalyst onto a polystyrene (PS) core template. Different sizes of the PS core (about 280 and 450 nm) and weight ratios of PS/DA were applied to elucidate the effect of the hollow diameter and thickness of the shell on the morphology and absorbance of the synthesized h-PDA. From UV absorption results, it was observed that the synthesized h-PDA particles with a larger core diameter (about 450 nm) and a thin shell thickness (about 57 nm) presented high UV absorption. We found that the structure of the synthesized h-PDA is mainly composed of a mixture of 5,6-dihydroxyindole and indole-5,6-quinone precursors covalently linked together. After blending the h-PDA particles with the base cream, the formulation containing h-PDA with a large void diameter of about 450 nm showed the highest sun protection factor (SPF) of up to 7.43, which is related to % booster of 234.7%. In addition, the h-PDA particles exhibited biocompatibility and cellular uptake in keratinocyte HaCaT cells after 24 h of incubation, indicating the potential to mimic natural melanin in preventing UV-induced DNA damage, which could be safely used as an alternative sunscreen.

Increased sensitivity of enterotoxigenic Escherichia coli detection in stool samples using oligonucleotide immobilized-magnetic nanoparticles.

PCR detection of enterotoxigenic Escherichia-coli (ETEC) can be used directly on stool sample. However, it still has limitations due to presence of PCR inhibitors and interferences. This study, oligonucleotide primer specific to ETEC was immobilized onto MNPs and applied for separation and enrichment of ETEC-DNA from contaminants in stool after boiling. DNA separation efficiency was evaluated using conventional PCR and magneto-PCR-enzyme linked-gene-assay (MELGA). Due to high specificity of primer and efficiency of nanoparticles to bring down PCR inhibitors, DNA separation using primer-immobilized-MNPs exhibited 100-fold increase of sensitivity compared to that using simple boiling. Moreover, the sensitivities in stool were increased from 108 to 106 CFU/mL and 104 to 102 CFU/mL when PCR products were detected by gel electrophoresis and MELGA, respectively. Results suggested that oligonucleotide-immobilized-MNPs combined with boiling DNA extraction method was successfully used to separate the DNA of ETEC in stool with high sensitivity using MELGA.

Heat-enhancing aggregation of gold nanoparticles combined with loop-mediated isothermal amplification (HAG-LAMP) for Plasmodium falciparum detection.

Malaria infection represents a major public health and economic issue that leads to morbidity and mortality globally. A highly effective and uncomplicated detection tool is required for malaria control in geographical hotspots of transmission. We developed a simple and more sensitive novel approach for the detection of the 18S rRNA gene of Plasmodium falciparum based on loop-mediated isothermal amplification (LAMP) and visualization using colorimetric, streptavidin-functionalized gold nanoparticles (SA-GNPs). Two loop primers of LAMP were biotinylated to produce biotin-containing products during amplification. After the addition of SA-GNPs, clusters of avidin-biotin complexes were established in the LAMP structure. While the positive reactions remained wine red, the negative reactions became colorless with partial aggregations induced by hydrochloric acid (HCl) under heat enhancement (60 °C). All steps of the assay were completed within 50 min, its detection limit was 1 parasite/µL, and it was highly specific for P. falciparum. This effortless detection system with high sensitivity and specificity could provide an alternative choice for malaria diagnostics in resource-limited regions.

A model of modified meta-iodobenzylguanidine conjugated gold nanoparticles for neuroblastoma treatment.

Iodine-131 meta-iodobenzylguanidine (131I-mIBG) has been utilized as a standard treatment to minimize adverse side effects by targeting therapies to bind to the norepinephrine transporter (NET) expressed on 90% of neuroblastoma cells. However, only a minority of patients who receive 131I-mIBG radiotherapy have clinical responses, and these are usually not curative. In this study, novel ligand-conjugated gold nanoparticles (GNPs) based on mIBG were synthesized and evaluated biologically with neuroblastoma cells in vitro. To induce specific internalization to the tumor cells and utilize it as a model for radioenhancement, 127I-modified mIBG was successfully synthesized and grafted covalently to the surface of carboxylated PEG-GNPs. 49.28% of the novel mIBG derivative was grafted on carboxylated PEG-GNPs. The particles were stable and not toxic to the normal fibroblast cell line, L929, even at the highest concentration tested (1013 NPs per mL) at 24, 48, and 72 h. Moreover, the cellular uptake of the model was decreased significantly in the presence of a NET inhibitor, suggesting that there was specific internalization into neuroblastoma cells line (SH-SY5Y) via the NET. Therefore, this model provides useful guidance toward the design of gold nanomaterials to enhance the efficiency of 131I-mIBG treatment in neuroblastoma patients. However, the investigation of radio-therapeutic efficiency after radioisotope 131I substitution will be further conducted in a radiation safety laboratory using an animal model.

Development of loop-mediated isothermal amplification (LAMP) assay using SYBR safe and gold-nanoparticle probe for detection of Leishmania in HIV patients.

Asymptomatic leishmaniasis cases have continuously increased, especially among patients with HIV who are at risk to develop further symptoms of cutaneous and visceral leishmaniasis. Thus, early diagnosis using a simple, sensitive and reliable diagnostic assay is important because populations at risk mostly reside in rural communities where laboratory equipment is limited. In this study, the highly sensitive and selective determination of Leishmania infection in asymptomatic HIV patients was achieved using dual indicators (SYBR safe and gold-nanoparticle probe; AuNP-probe) in one-step LAMP method based on basic instruments. The assay can be simply evaluated under the naked eye due to clear interpretation of fluorescent emission of LAMP-SYBR safe dye-complex and colorimetric precipitate of specific AuNP-probes. The sensitivities and specificities of fluorescent SYBR safe dye and AuNP-probe indicators were equal, which were as high as 94.1 and 97.1%, respectively. Additionally, detection limits were 102 parasites/mL (0.0147 ng/µL), ten times more sensitivity than other related studies. To empower leishmaniasis surveillance, this inexpensive one-step SYBR safe and AuNP-LAMP assay is reliably fast and simple for field diagnostics to point-of-care settings, which can be set up in all levels of health care facilities including resource limited areas, especially in low to middle income countries.

Near-infrared polyfluorene encapsulated in poly(ε-caprolactone) nanoparticles with remarkable large Stokes shift.

Near-infrared (NIR) fluorescent dyes have attracted increasing attention as fluorescent probes in biomedical applications due to their low biological autofluorescence as well as high tissue penetration depth. However, their being hydrophobic in nature limits their clinical use as they are prone to aggregate in the physiological environment. Herein, we have designed and synthesized a novel polymeric NIR fluorescent dye and then encapsulated it into a poly(ε-caprolactone) (PCL) matrix by way of an emulsion-diffusion technique. The effect of the structure of the surfactant on the nanoparticle properties is investigated. Results show that polymeric surfactant, Kolliphor® P188, allows the formation of a high fluorescence intensity of the nanoparticles with the highest level homogeneity and stability. The synthesized nanoparticles show significant advantages in terms of a remarkable large stokes shift (276 nm) in the aqueous solution and excellent biocompatibility. The fabrication process is not limited to encapsulation of polymeric fluorescent dye. The synthesized NIR polymeric nanoparticles would be potentially applicable for biomedical applications.

Fabrication of functional hollow magnetic polymeric nanoparticles with controllable magnetic location.

Hollow magnetic polymeric particles (HoMPs) with controllable location of magnetic nanoparticles and functionality of polymeric double shell were fabricated by means of the facile soft templating method in one-pot. During the in situ miniemulsion polymerization, hexadecane, the Ostwald suppressing agent, acted as a soft template, which later formed a controllable void size. Adjusting ratio and polarity of monomers caused the difference in polymerization kinetics and phase separation, which resulted in HoMPs with two internal architectures, i.e., HoMPs-I with magnetic at the inner shell/void interface and HoMPs-II with magnetic-embedded shell. Both HoMPs-I and II contained high magnetic content (30-50%wt) with sufficient saturation magnetization (16-30 emu/g). With large void volume (>50%) and distinct shell polarity, either hydrophilic Rhodamine B or hydrophobic fluorescein isothiocyanate dye was selectively loaded. After functionalization with a cancer cell targeting ligand, folic acid (FA), the cellular uptake of HoMPs-FA in HeLa cell was improved with 100% cell viability and without cell destruction. This fabrication method provides a facile mean to tailor surface chemistry and architectures of hollow hybrid particles, which would be potentially used for efficient treatment of cancer tumors.

PMMA particles coated with chitosan-silver nanoparticles as a dual antibacterial modifier for natural rubber latex films.

The antibacterial activity in sulphur prevulcanized natural rubber (SPNR) latex film was effectively improved by deposition of poly(methyl methacrylate) (PMMA) particles encircled with chitosan-coated silver nanoparticles (AgNPs-CS). With the focus on a green process, CS was selected as a safe reducing and stabilizing agent for the one-step synthesis of AgNPs-CS (38 nm, +40.4 mV) in an autoclave. The adsorption of small-sized AgNPs-CS directly onto rubber film did not provide an inhibitory effect on S. aureus. It also had a low antibacterial effect on E. coli. This is because of the particles becoming completely/partially submerged into the soft rubber matrix upon drying. Hence, the AgNPs-CS were fabricated as a shell surrounding a rigid PMMA core (496 nm, -30.9 mV). This was done using a heterocoagulation technique prior to coating on SPNR film. The presence of PMMA/AgNPs-CS on the surface of SPNR film effectively increased the surface roughness from ca. 44 to 150 nm. This substantially promoted the antibacterial activity against E. coli and S. aureus by way of contact killing and repelling mechanisms. The cytotoxicity on L-929 fibroblasts was also suppressed. This study would be, therefore, applicable to the development of antibacterial SPNR film with high surface roughness, low cytotoxicity. It could also be applied for other soft substrates.

One-pot, large-scale green synthesis of silver nanoparticles-chitosan with enhanced antibacterial activity and low cytotoxicity.

Silver nanoparticles stabilized with chitosan (AgNPs-CS) were synthesized based on the one-pot green process in an autoclave, in which CS acts as reducing agent as well as stabilizer. Effects related to temperature and pressure input on particle formation were systematically investigated. Mechanism taking place during particle nucleation and growth was proposed. The data from UV-vis absorption, X-ray diffraction pattern and morphology confirmed the formation of AgNPs-CS with face-centered cubic (fcc) structure. The synthesized AgNPs-CS showed the effective antibacterial activity against both E. coli and S. aureus. The minimum bactericidal concentration values of 39.1 and 312.5 µg/ml for E. coli and S. aureus, respectively, did not show cytotoxicity to L-929 fibroblast. Moreover, the covering of CS on the surface of AgNPs-CS was proven to reduce the cytotoxicity when compared with commercial citrate-stabilized AgNPs. Considering simple and mild process, this synthesis approach would be helpful for development of benign AgNPs-based antibacterial agent.

Enrichment of human Vγ9Vδ2 T lymphocytes by magnetic poly(divinylbenzene-co-glycidyl methacrylate) colloidal particles conjugated with specific antibody.

γδ T cells play a significant role in protection against cancer. Purification of γδ T cells is needed for insight when studying their anti-cancer functionality and their utilization in adoptive cell therapy. To improve the purification of γδ T cells, in this work, a composite material based on magnetic nanoparticles was developed for purification of Vγ9Vδ2 T cells, the predominant subset of γδ T lymphocytes in human peripheral blood. The epoxy-functionalized magnetic poly(divinylbenzene-co-glycidyl methacrylate) particles (mPDGs) were bio-conjugated with anti-human Vδ2 antibody to provide specific recognition sites for T cell receptors of Vγ9Vδ2 T cells. Using fluorescence-activated cell sorting (FACS) analysis, separation of Vγ9Vδ2 T cells from peripheral blood mononuclear cells of healthy donors was confirmed with high purity [89.77% (range 87.00-91.80, n = 3)]. More interestingly, the immobilized particles did not affect the viability of purified cells as high cell viability was indicated (>90%). By combining the properties of magnetic nanoparticles with specific antibodies, these immobilized particles were shown to be used as a cell-friendly purification tool of Vγ9Vδ2 T lymphocytes without any limits for the further use of cells. The purified Vγ9Vδ2 T cells using the antibody-immobilized epoxy-functionalized mPDGs could be used directly without a detachment step for further cultivation and expansion. This highlights the advantages of this method in allowing the study of cell function and further investigation of such rare T cell populations in immunotherapy.

Magnetic particles for in vitro molecular diagnosis: From sample preparation to integration into microsystems.

Colloidal magnetic particles (MPs) have been developed in association with molecular diagnosis for several decades. MPs have the great advantage of easy manipulation using a magnet. In nucleic acid detection, these particles can act as a capture support for rapid and simple biomolecule separation. The surfaces of MPs can be modified by coating with various polymer materials to provide functionalization for different applications. The use of MPs enhances the sensitivity and specificity of detection due to the specific activity on the surface of the particles. Practical applications of MPs demonstrate greater efficiency than conventional methods. Beyond traditional detection, MPs have been successfully adopted as a smart carrier in microfluidic and lab-on-a-chip biosensors. The versatility of MPs has enabled their integration into small single detection units. MPs-based biosensors can facilitate rapid and highly sensitive detection of very small amounts of a sample. In this review, the application of MPs to the detection of nucleic acids, from sample preparation to analytical readout systems, is described. State-of-the-art integrated microsystems containing microfluidic and lab-on-a-chip biosensors for the nucleic acid detection are also addressed.

Combination of PCR and dual nanoparticles for detection of Plasmodium falciparum.

Highly reactive particle-based DNA amplification was developed for the detection of the Pfg377 gene from P. falciparum gametocytes using functional magnetic latex particles (MLPs) and quantum dots encapsulated polymer particles (QDs-PPs). Firstly, MLPs were prepared from the precipitation of iron oxide, polymerization using initiator, and adsorption of aminodextran (AMD) so as to provide amino-functionalized MLPs. Furthermore, amino-containing polymer particles (PPs) were prepared by emulsifier-free polymerization and encapsulated with fluorescent quantum dots (QDs) for use as a signaling support. Subsequently, poly(maleic anhydride-alt-methyl vinyl ether) (PMAMVE) copolymer was effectively used for rapid and simple grafting of amino-modified DNA primers onto the surface of amino-functionalized particles thereby providing a promising method for particle immobilization. Herein, primer-grafted particles were applied in the amplification of the Pfg377 gene using the PCR approach. After amplification, PCR products containing PMAMVE-grafted MLPs and QDs-PPs were separated using a magnet and examined via a fluorescence microscope. PMAMVE-grafted particles were not found to inhibit the PCR reaction while facilitating efficient fluorescent detection of the PCR product. Results showed high sensitivity and specificity for the detection of amplified Pfg377 gene within only a few steps. This procedure represents a novel improvement to the post-amplification analysis.