Target capturing performance of microfluidic channel surface immobilized aptamers: the effects of spacer lengths

Qin, Yubo; Yang, Xiuying; Zhang, Jingchang; Cao, Xudong

doi:10.1007/s10544-019-0403-z

Cited by 12 publications

(10 citation statements)

References 39 publications

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“…Thus, since the first RNA aptamer developed in 1992,23 aptamers have been extensively developed and used in clinical diagnostics, therapeutic agents and tissue engineering applications. There have several works of literature reported that aptamer can capture and enrich targeting cells with relatively high efficiency and accuracy, and aptamer has been widely used in the capture of circulating tumor cells (CTCs) 24–26. Thus, an aptamer-directed repair system capable of selective recruitment of MSCs to the comminuted fracture defect site would open a new promising path for bone defect repair.…”

Section: Introductionmentioning

confidence: 99%

<p>Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment</p>

Wang¹,

Wu²,

Qiao³

et al. 2019

IJN

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BackgroundThe restoration and repair method in the clinic of delayed fracture healing and non-union after comminuted fractures are urgently needed to improve the prognosis of patients. The recruitment of endogenous stem cells has been considered a promising approach in bone defect repair.ProposeThe aim of this study was to generate a de novel MSCs aptamer and developed the first, feasible, economical, bio-compatible, and functional MSCs aptamer-directed nanoparticles without complex manufacture to recruit mesenchymal stem cells (MSCs) for bone defect regeneration.MethodsWhole-cell SELEX was used to generate a de novel MSCs aptamer. Flow cytometry was applied to assess the binding specificities, affinities and sorting abilities of the aptamers. Nano-Aptamer Ball (NAB) was constructed by NHS/EDC reaction. The diameter and zeta of NAB were assessed by dynamic light scattering. CCK8 assay was utilized to evaluate whether NAB could cause non-specific cytotoxicity and induce cell proliferation. To evaluate the bone repair capacity of NAB, histomorphological staining, alizarin red and micro X-ray were used to observe the repair degree of defect in vivo. ELISA was used to detect osteopontin (OPN), osteocalcin (BGP) by, and alkaline phosphatase (ALP) in peripheral blood.ResultsMSCs aptamer termed as HM69 could bind with MSCs with high specificity and Kd of 9.67 nM, while has minimal cross-reactivities to other negative cells. HM69 could capture MSCs with a purity of >89%. In vitro, NAB could bind and capture MSCs effectively, whereas did not cause obvious cytotoxicity. In vivo, serum OPN, BGP, and ALP levels in the NAB group of rats were increased at both 2 and 4 weeks, indicating the repair and osteogenesis generation. The healing of bone defects in the NAB group was significantly better than control groups, the defects became blurred, and local trabecular bone growth could be observed in X-ray. The organized hematoma and cell growth in the bone marrow of the NAB group were more vigorous in bone sections staining.ConclusionThese suggested that HM69 and HM69-functionalized nanoparticles NAB exhibited the ability to recruit MSCs both in vitro and in vivo and achieved a better outcome of bone defect repair in a rat model. The findings demonstrate a promising strategy of using aptamer-functionalized bio-nanoparticles for the restoration of bone defects via aptamer-introduced homing of MSCs.

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Section: Introductionmentioning

confidence: 99%

<p>Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment</p>

Wang¹,

Wu²,

Qiao³

et al. 2019

IJN

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“…Moreover, when surface-based aptasensors are considered, incorporation of a spacer to extend the binding region of the aptamer from the surface and minimize steric hindrance effects may also improve the aptamer functionality. The spacer can be a polyethylene glycol moiety fused with the aptamer sequence or on the surface, or by direct sequence elongation, such as the introduction of several thymine bases [102,103,109,111,[113][114][115]. The last aspect to be considered is preventing undesired electrostatic interactions between the negatively-charged aptamers and positively-charged surfaces, which may impede the aptamer's folding; this can be achieved via surface modification or passivation strategies [100,102].…”

Section: Aptasensor Design Considerationsmentioning

confidence: 99%

Aptasensors versus immunosensors—Which will prevail?

Arshavsky‐Graham

Heuer

Xin

et al. 2022

Engineering in Life Sciences

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Since the invention of the first biosensors 70 years ago, they have turned into valuable and versatile tools for various applications, ranging from disease diagnosis to environmental monitoring. Traditionally, antibodies have been employed as the capture probes in most biosensors, owing to their innate ability to bind their target with high affinity and specificity, and are still considered as the gold standard. Yet, the resulting immunosensors often suffer from considerable limitations, which are mainly ascribed to the antibody size, conjugation chemistry, stability, and costs. Over the past decade, aptamers have emerged as promising alternative capture probes presenting some advantages over existing constraints of immunosensors, as well as new biosensing concepts. Herein, we review the employment of antibodies and aptamers as capture probes in biosensing platforms, addressing the main aspects of biosensor design and mechanism. We also aim to compare both capture probe classes from theoretical and experimental perspectives. Yet, we highlight that such comparisons are not straightforward, and these two families of capture probes should not be necessarily perceived as competing but rather as complementary. We, thus, elaborate on their combined use in hybrid biosensing schemes benefiting from the advantages of each biorecognition element.

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“…With properly selected lengths and materials, spacers can increase the avidities of multivalent constructs by overcoming steric hindrances due to adjacent aptamers. The most common spacers are PEG [ 77 , 78 ]; alkyl [ 78 , 79 ]; ssDNAs, such as oligo-T and oligo-A [ 78 , 80 , 81 ]; and dsDNA [ 82 ]. Among these different types of spacers, oligo-T spacers are perhaps the most commonly used [ 75 ]; therefore, in this section, we focus on oligo-T spacers.…”

Section: Design Strategiesmentioning

confidence: 99%

“…A spacer with properly designed length should both support the aptamer sequence and allow the aptamers to stand out from the conjugated surface or backfilling molecules [ 83 ]. Surface-immobilized aptamers with no or short spacer lengths experience impairments in freedom motions [ 84 ], while long spacer lengths can be too long to ensure correct folding of either the aptamers [ 81 ] or the spacers themselves [ 85 ] for correct secondary structures. For instance, Qin and coworkers [ 81 ] demonstrated the importance of spacer length by conjugating sgc8 aptamers onto poly(amidoamine) (PAMAM) dendrimers via oligo-Ts of lengths from 2 to 20 nucleotides for capturing circulating tumor cells (CTCs).…”

Section: Design Strategiesmentioning

confidence: 99%

“…Surface-immobilized aptamers with no or short spacer lengths experience impairments in freedom motions [ 84 ], while long spacer lengths can be too long to ensure correct folding of either the aptamers [ 81 ] or the spacers themselves [ 85 ] for correct secondary structures. For instance, Qin and coworkers [ 81 ] demonstrated the importance of spacer length by conjugating sgc8 aptamers onto poly(amidoamine) (PAMAM) dendrimers via oligo-Ts of lengths from 2 to 20 nucleotides for capturing circulating tumor cells (CTCs). The researchers observed that excessively long spacers resulted in unfavorable alterations in aptamer secondary structures, thereby negatively impacting the capturing performance.…”

Section: Design Strategiesmentioning

confidence: 99%

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Multivalent Aptamer Approach: Designs, Strategies, and Applications

et al. 2022

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Aptamers are short and single-stranded DNA or RNA molecules with highly programmable structures that give them the ability to interact specifically with a large variety of targets, including proteins, cells, and small molecules. Multivalent aptamers refer to molecular constructs that combine two or more identical or different types of aptamers. Multivalency increases the avidity of aptamers, a particularly advantageous feature that allows for significantly increased binding affinities in comparison with aptamer monomers. Another advantage of multivalency is increased aptamer stabilities that confer improved performances under physiological conditions for various applications in clinical settings. The current study aims to review the most recent developments in multivalent aptamer research. The review will first discuss structures of multivalent aptamers. This is followed by detailed discussions on design strategies of multivalent aptamer approaches. Finally, recent developments of the multivalent aptamer approach in biosensing and biomedical applications are highlighted.

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Target capturing performance of microfluidic channel surface immobilized aptamers: the effects of spacer lengths

Cited by 12 publications

References 39 publications

<p>Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment</p>

<p>Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment</p>

Aptasensors versus immunosensors—Which will prevail?

Multivalent Aptamer Approach: Designs, Strategies, and Applications

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