Table 1.

Basic membrane structure characteristics, main strengths and limitations of commercially available hemodialysis hollow-fiber membranes

Category	Membrane name	Basic membrane structure characteristics					Main strengths and limitations	References
		Composition	Structure	Pore radius (Å)	Wwall thickness (μm)	Ultrafiltration coefficient (ml/hr/mmHg)
Cellulosic membrane	(Unmodified) cuprophane membrane	Cellulose	Symmetric	21	5–17	Low-flux (3.8 -8.4)	Negligible middle molecule removal, significant complement activation and leukopenia, only for standard hemodialysis	[56–58]
	Cellulose triacetate membrane	Cellulose triacetate	Symmetric	58 ~ 78	15	Low- to high-flux (9.5–85.6)	Minimal protein adsorption, attenuated complement activation, high antithrombotic performance, high phosphorus clearance, improved lipid metabolism	[25, 59–62]
	Cellulose (di) acetate membrane	Cellulose diacetate	Symmetric	NA	14–30	Low- to high-flux	Improved biocompatibility and hydrophobicity vs cuprophane membrane, low middle molecule removal	[24, 63]
	Hemophan membrane	Cellulose and diethylaminoethyl	Symmetric	21	5–20	Low-flux	Negligible middle molecule removal, improved biocompatibility and hydrophobicity vs cuprophane membrane, higher pro-inflammatory cytokine production than polyamide membrane, only for standard hemodialysis	[24]
	Cuprammonium rayon membrane	Polyethylene and cellulose	Asymmetric	NA	9–26	Low- to high-flux (9–19)	Improved biocompatibility and hydrophobicity vs cuprophane membrane, less platelet activation and higher albumin loss vs polysulfone membrane	[15, 24, 64, 65]
Synthetic membrane	AN69 membrane	Copolymer of acrylonitrile and sodium methallyl sulfonate	Symmetric	25–55	30	High-flux (19.42)	With a specific hydrogel structure on its surface; bulk adsorption of low-molecular-weight proteins such as cytokines; decreased complement activation, platelet adhesion and activation; increased activation of kallikrein-kinase system, production of bradykinin, available for high-flux hemodialysis, hemodiafiltration, and hemofiltration	[24, 66]
	PAN membrane	Copolymer of acrylonitrile, methacrylate and acrylic acid	Asymmetric	NA	19–55	High-flux (45–54)	Yield of bradykinin, risk of allergic reactions higher than other synthesis membranes, sustained mild complement activation	[15, 67]
	PSF membrane	Polysulfone, blending with polyvinylpyrrolidone or polyethylene glycol in most occasions	Asymmetric	NA	30–104	Low- to high-flux	Meets solute and fluid removal needs in all therapy modalities (low and high throughput dialysis, in-line hemofiltration and hemofiltration), efficient endotoxin retaining capacity, significant intrinsic biocompatibility, low cytotoxicity, the most widely used dialysis membrane in routine hemodialysis, Optimal chemical and thermal stability for steam sterilization, Increased β2 macroglobulin clearance through advanced PSF-based Helixone® without any albumin loss	[6, 24, 26]
	PMMA membrane	Isotactic and syndiotactic polymethylmethacrylate	Asymmetric	NA	20–40	Low- to high-flux	Reduced complement activation compared to cuprophane membranes with increased removal of β2 microglobulin by adsorption, sustained mild complement activation, and unexpected slight leukopenia	[10, 15, 24, 28]
	PES membrane	Polyethersulfone, blending with polyvinylpyrrolidone in most occasions	Asymmetric	NA	30–104	Low- to high-flux	Meets solute and fluid removal needs in all therapy modalities (low and high throughput dialysis, in-line hemofiltration and hemofiltration), provides significant intrinsic biocompatibility, favorable chemical and thermal stability, allows for steam sterilization, and delivers dialysate uniformly through Diapes®	[24, 30]
	EVOH membrane	Copolymer of ethylene and vinyl alcohol	Symmetric	NA	25–32	Low-flux (5.8–11.1)	Smooth inner surface; few plasma protein adsorption; weak interactions with blood cells	[24, 68]
	MCO membrane	Polyethersulfone, blending with polyvinylpyrrolidone	Asymmetric	50	35	High-flux (48–59)	Medium apertures, uniform distribution of pores, steep sieve curve and internal filtration–backfiltration mechanism, greater removal of middle-molecule toxins than conventional high-flux dialysis, insufficient removal of protein-bound and large-molecule uremic toxins and unwanted albumin loss	[31, 33]
Bioactive membrane	AN69ST membrane	Copolymer of acrylonitrile and methallylsulfonate (AN69) coated with polyethyleneimine	Symmetric	NA	45	High-flux	Lower surface charge, kallikrein-kinase system activation and high-molecular weight protein adsorption than AN69 membrane due to surface treatment technique with cationic polyethyleneimine, specific antithrombin III adsorption by binding to heparin coating, unique self-anticoagulant membrane for heparin-free dialysis	[27, 69, 70]
	HeprAN membrane	Copolymer of acrylonitrile and methallylsulfonate (AN69) coated with polyethyleneimine and heparin	Symmetric	NA	45	High-flux	Further superficial treatment by cationic polyethyleneimine polymer and grafting of heparin on the inner surface, specific antithrombin III adsorption by binding to heparin coating, unique self-anticoagulant membrane for heparin-free dialysis, effective endotoxin retention capacity	[27, 69]
	Vitamin-E coated membrane	Cellulose-based or polysulfone-based membrane coated with vitamin-E	NA	NA	NA	Low- to high-flux	Decreased oxidative stress, improved inflammation status and anemia, persistence of complement activation	[15, 52, 55, 71, 72]