Table 1.

Summary of aptamer–CRISPR areas of application.

Specific Application	Aptamer Type	CRISPR/Cas System	Pros	Cons	Types of Application	Reference
Improvement of CRISPR specificity and off-target effects	DNA/RNA	Cas9	Dose-dependent activation/inactivation On-target sgRNA allows for high regulation of multiple genes Inhibitory aptamers can bind Cas9 at low affinities	Control only under specific conditions Regulation of genome editing in reverse Potential risk of immunogenicity and toxicity	Genomic editing/therapeutic/diagnostics/research	[53,54,55,56,57]
Osteosarcoma	DNA	Cas9	Inhibits osteosarcoma and lung metastasis effectively Reduce VEGFA expression/secretion Decreased angiogenesis	Studies in mice do not completely translate to humans Use of lipopolymers only in phase II trials	Therapeutic	[58]
Prostate cancer	RNA	Cas9	Highly flexible for liposome modifications to target a myriad of diseases Highly selective for prostate cancer cells (specifically polo-like kinase 1) in vitro No significant toxicity Safer than cationic liposome	Requires the appropriate modification for highest efficacy	Therapeutic	[59]
Tumor-derived extracellular vesicle protein	DNA	Cas12a	Simple and easy to operate High affinity for surface protein targets on TEVs Clinically feasible and cost-effective	Kinetic efficiency is low Requires optimal conditions (i.e., hairpins with large loops, specific heating temperatures/durations)	Diagnostics	[60]
Nasopharyngeal carcinoma	DNA	Cas12a	Sensitive, specific detection of surface proteins Detects CD109+ and EGFR+ TEVs, good biomarkers for NPC diagnosis Small batch variation Stable and simple	Can only do one marker per run, lowers the accuracy of detection Low ability to determine specific amounts of each target protein Uses PCR, which requires cooling/heating cycles. Therefore, heat-stable DNA is required. Cost of RPA increases detection cost	Diagnostics	[61]
Chromatin Imaging	RNA	Cas9	Specific two-color labeling of repeating sequences Signal-to-background ratio enhanced in chromatin imaging	Not used on non-repetitive sequences yet Involves an extra protein construct compared to other methods Cell-line construction is more complex than other models	Imaging, Research	[62]
Mycotoxin Detection	DNA	Cas12a	Does not require sophisticated equipment Detection limit at 0.05 ng/L Highly selective for AFM1 Synthesis of old nanoparticles is convenient	Only tested in milk samples	Biosafety	[63]
Native membrane protein detection	DNA	Cas9	SELEX uses isogenic cell lines to specifically bind GLUT1 transporter Can be used to create reagents that bind a variety of specific cell membrane proteins in native conformation	Did not examine off-target CRISPR edits The efficiency of selection reduced by unintended effects of the SELEX procedure used SELEX process might have induced unintended mutations in cells Homologous family members not removed, reducing the hit rate of specific aptamers	Therapeutic, Diagnostic	[66]
Immunoassay	DNA	Cas12a	Direct relationship between non-nucleic acids and CRISPR-Cas12a system examined Can be directly used in enzyme-linked immunosorbent assay Simple for biosensing High detection for small molecules and tumor cells Nanoprobes easy to manufacture	The efficiency of the detection platform still needs to be improved	Diagnostics	[68]
Small Molecule Bioassay (ATP)	DNA	Cas12a	ATP detect method has high sensitivity and selectivity Novel characteristics of CRISPR-Cas12a described Novel fluorescent biosensor used fDNA-regulated CRISPR useful in point-of-care and field tests	Requires costly fluorescent reader for biosensors ATP biosensors are limited by oligonucleotide design The portable fluorimeter-based method shows reduced analytical performance	Diagnostics	[68,69,70]
Transforming Growth Factor 1 (TGF-1)	DNA	Cas12a	Rapid, cost-effective E-CRISPR highly specific for small viral nucleic acids Able to accurately quantify TGF-1	Steric hindrance effect of Cas endonuclease limited activity of trans-cleavage High concentrations reduced activity of Cas12a, leading to decreased diffusion	Diagnostics	[71]
Interferon-gamma	DNA	Cas12a	Sensitive detection of the target in complex biological samples	Special equipment is needed for fluorescent signal detection	Diagnostics	[72]
Viral myocarditis–Cardiac Troponin I	DNA	Cas12a	Sensitive detection of the target in mouse serum samples	Complex setup using upconversion nanoparticles and 3D photonic crystal	Diagnostics	[73]
SARS-CoV-2 Detection	RNA DNA DNA	Cas13 Cas12a Cas12a	Sensitive and rapid detection of pathogenic SARS-CoV-2 variants Detection of low viral titer	Diagnose active infection only	Diagnostics	[75] [75] [76]
Methicillin-resistant Staphylococcus aureus (MRSA) Detection	DNA DNA	Cas12a	Accurate and sensitive bacterial detection Decreased cost enabling worldwide use	Components of clinical samples may impair aptamer target binding	Diagnostics	[77] [78]
Bacillus cereus Detection	RNA	Cas13a	Ability to detect live pathogenic bacteria Accurate estimation of food spoilage	Limited to Bacillus cereus detection	Biosafety	[79]
Salmonella typhimurium Detection	DNA	Cas12a	Highly sensitive detection of live bacteria in milk samples	Highly dependent on fine tuning the aptamer concentration on sensor surface	Food safety	[80]