Dr. Miron's PRF Protocols — Horizontal Centrifugation and the Modern Science

Who is Dr. Miron and why he matters

Dr. Richard J. Miron is a researcher and clinician affiliated with the University of Bern, Switzerland, and previously the University of Buffalo. He holds a doctorate in cell biology and is one of the most-cited authors in regenerative dentistry and aesthetic regenerative medicine. Over the past decade his group has published more than 100 peer-reviewed papers specifically on PRF preparation, characterization, and clinical application — including two comprehensive textbooks (Platelet Rich Fibrin in Regenerative Dentistry: Biological Background and Clinical Indications, Wiley, 2017; and Platelet Rich Fibrin in Plastic and Reconstructive Surgery and Esthetic Medicine, Quintessence, 2024).

The reason his name keeps appearing isn't celebrity. The reason is that PRF as a category is highly protocol-sensitive. Two clinics using the same product name can produce very different cellular preparations depending on which protocol they run. Miron's group did the systematic comparative work that revealed exactly how much protocol choice matters — and that work changed the standard.

Almost all modern PRF clinical guidelines now reference Miron-protocol methodology, even when the commercial product comes from a different manufacturer. The protocols have become the de-facto standard, in the same way that specific surgical techniques become standard regardless of who marketed the instruments.

PRF before Miron: where it started

PRF was originally developed by Dr. Joseph Choukroun in France in 2001 as an alternative to PRP for dental and surgical regeneration. Choukroun's original protocol used glass-coated tubes (no anticoagulant) and a single centrifugation step at 2,700 rpm for 12 minutes in a fixed-angle centrifuge. The result was a solid fibrin clot — what we now call L-PRF (leukocyte-rich PRF).

For roughly a decade, this was "PRF": a single protocol producing a single product, used mainly in dental and oral-surgical contexts. The clinical results were good enough that the technique spread, but two limitations were obvious to researchers:

• The solid clot couldn't be injected. It worked as a membrane or graft material, but not for facial aesthetic injection.
• The high-speed protocol may have been damaging cells. Early research suggested platelets were activating prematurely in the centrifuge tube, releasing growth factors there rather than at the injection site.

Around 2014–2017, several research groups — Miron's prominently — began systematically varying centrifugation parameters to see what was actually happening at the cellular level. The work that emerged reshaped the field.

Horizontal centrifugation: the physics

Conventional lab centrifuges use a fixed-angle rotor — tubes sit at a 25–45° angle to the rotation axis. During spinning, cells migrate toward the outer wall of the tube along an angled vector. The result is that separation happens both down the tube and across it, producing slanted, uneven layers.

For most lab applications this is fine: you want to separate plasma from cells, the slight angle doesn't matter, you decant the top layer. But for PRF, where the clinical product is the precise composition of the upper layer, the angled separation is a significant problem:

• Platelets and leukocytes get distributed unevenly through the plasma column.
• The buffy coat (the cellular layer of interest) sits at an angle, making it hard to isolate cleanly.
• Some cells get pinned against the tube wall, never reaching the plasma layer at all.

A horizontal (swing-bucket) centrifuge rotates the tubes outward during spinning so they sit perpendicular to the rotation axis — truly horizontal. Cells migrate along a single vector: straight down the tube. The result is clean, horizontal layering throughout the entire tube, not just locally.

Miron's group quantified the difference. In a 2019 head-to-head study (Miron et al., Clinical Oral Investigations), horizontal centrifugation produced:

• ~3× higher platelet concentration in the recovered PRF layer compared to fixed-angle
• Significantly more uniform cell distribution — particularly important for leukocyte yield
• Better reproducibility between batches, even between different operators
• Cleaner separation from the red blood cell layer, reducing red cell contamination of the final product

The findings have been independently reproduced. Horizontal centrifugation is now the de-facto standard for aesthetic PRF.

The Low-Speed Centrifugation Concept (LSCC)

Parallel to the horizontal-vs-fixed-angle question, Miron's group also investigated the other major variable: centrifugation speed. The original 2,700 rpm Choukroun protocol was based on practical considerations — producing a stable clot in reasonable time — not on optimizing growth factor preservation.

The Low-Speed Centrifugation Concept (LSCC), introduced by Choukroun and Ghanaati in 2018 and refined by Miron's group, holds that lower centrifugation forces preserve cell integrity better:

• High G-forces shear platelets. Platelets are mechanically fragile. Excessive centrifugation activates them prematurely — they degranulate inside the tube, releasing growth factors that are then trapped in the centrifuge consumable rather than delivered to tissue.
• High G-forces crush leukocytes. Leukocyte concentration in the final product drops as centrifugation force increases. Since leukocytes contribute meaningfully to PRF's immune-modulating effects, preserving them matters.
• Stem and progenitor cells are particularly fragile. The small mesenchymal-cell and CD34+ progenitor populations are nearly absent in high-speed PRF but well-represented in low-speed protocols.

The practical result: i-PRF, the injectable liquid form, is now prepared at 200–300 g for 5 minutes per Miron's optimized 24-protocol grid^5,9 — a fraction of the original Choukroun parameters. Solid PRF runs at 700 g × 8 min, Alb-PRF uses the same i-PRF step at 200–300 g, and C-PRF (concentrated) runs at 2,000 g × 8 min⁶.

Published evidence: what the studies actually show

The protocol-optimization work has produced a substantial peer-reviewed evidence base. Selected key findings:

• Growth factor release profile (Miron 2017–2019): Modern horizontal-LSCC i-PRF releases PDGF, TGF-β1, VEGF, and EGF sustainably over 10 days, vs ~4 hours for high-speed PRP. The area-under-curve of total growth factor exposure is several-fold higher with LSCC i-PRF.
• Cell viability and concentration (Miron 2019, Choukroun & Ghanaati 2018): Horizontal LSCC preserves platelet integrity at >90% (vs ~60% for fixed-angle high-speed) and triples leukocyte yield.
• Clinical outcomes in facial rejuvenation (multiple groups, 2020–2023): Direct comparison studies between modern i-PRF and older PRP or older PRF protocols favor modern PRF on most aesthetic endpoints — skin quality scores, patient satisfaction, durability of effect.
• Alb-PRF for soft-tissue volume (Mourao, Miron 2020–2023): Heat-denatured albumin gel produces clinically meaningful volume retention at 3–6 months with concurrent biostimulation. Early studies show measurable improvement in tissue density compared to baseline at 6 months post-resorption.
• Hair restoration (multiple studies, 2018–2024): i-PRF produces measurable increases in hair density and thickness in androgenetic alopecia, with effect sizes comparable to or exceeding topical minoxidil monotherapy.

The studies aren't perfect — sample sizes vary, blinding is sometimes incomplete, follow-up periods could be longer — but the body of evidence is increasingly coherent and points consistently to modern protocols outperforming older ones.

The current Bio-PRF protocol library

What "Miron-protocol PRF" means in practice is a library of distinct preparations, each with its own centrifugation parameters and clinical use. The major members of this library:

• Solid PRF (formerly L-PRF) — for surgical membranes, dental grafting, wound closure. Higher speed, longer time, produces a removable fibrin clot.
• i-PRF (Injectable PRF) — injectable liquid for facial mesotherapy, under-eye treatment, scalp injection for hair. 200–300 g, 5 minutes.
• Alb-PRF (Albumin-Gel PRF) — i-PRF combined with heat-denatured autologous albumin (75°C). Produces a stable, durable gel for volume restoration. Lasts 3–6 months in tissue with concurrent biostimulation.
• e-PRF (Extended-release / Sticky PRF) — intermediate consistency. Used in mixed protocols, often with bone graft materials, sometimes in soft-tissue applications.
• C-PRF (Concentrated PRF) — a more recent addition. Super-concentrated growth-factor preparation used for high-demand cases like severe alopecia or aggressive scar revision.

The actual numbers (for the technically curious)

Specific protocols vary slightly between published Miron-group papers and the commercial Bio-PRF system, but representative values for the most common preparations:

All values are RCF (relative centrifugal force, in ×g) — not RPM. RPM is centrifuge-radius-dependent: a smaller-radius rotor at 1,000 rpm produces less force than a larger-radius rotor at the same speed. Miron's 2019 paper on this specifically calls for PRF protocols to be reported in g-force, not RPM³. Clinics that quote "our centrifuge runs at X rpm" without specifying machine and rotor radius are unintentionally signaling they may not have characterized their actual protocol.

Bio-PRF system vs other PRF systems

Several commercial PRF systems exist on the market beyond Bio-PRF: Salvin, IntraSpin/Intra-Lock, Choukroun PRF Box, and others. All can produce some form of PRF; not all are equivalent.

The key differentiators between systems:

• Centrifuge type: horizontal vs fixed-angle. Bio-PRF and a few others are horizontal; many older systems are fixed-angle.
• Tube specification: glass-coated, silica-coated, plastic. The tube affects clot formation kinetics; specific protocols require specific tubes.
• Protocol breadth: some systems support only one or two preparations (e.g., solid PRF only). Bio-PRF supports the full library.
• Quality control: validated batch consistency. The major systems have documented this; smaller systems may not.

From a clinical-outcomes standpoint, the system itself matters less than whether the operator runs validated, current protocols. A clinic using a non-Bio-PRF horizontal centrifuge with proper Miron-derived parameters is doing modern PRF. A clinic with the latest Bio-PRF equipment running outdated parameters isn't.

What to ask your clinic

If you want to know whether a clinic is running modern protocols, useful questions:

1. "Is your centrifuge horizontal or fixed-angle?" Horizontal is current. A fixed-angle answer doesn't disqualify the clinic but does indicate older methodology.
2. "Which specific protocol do you use for [your indication]?" A specific answer ("i-PRF at 200–300 g for 5 minutes for skin quality, Alb-PRF at 75°C albumin for volume") signals a clinic that has actually validated and chosen its protocols. A generic answer ("we do PRF") suggests one protocol used for everything.
3. "How fresh is the preparation when you inject?" The window is short — 15 to 45 minutes from spin to injection. Sitting around for hours degrades the product.
4. "Do you offer Alb-PRF?" Alb-PRF is the newest major advance and the most clinically valuable for volume work. Many clinics with PRF capability haven't adopted Alb-PRF yet. Its presence is a strong indicator of an updated practice.
5. "Can I see the protocol on the day of treatment?" Reasonable clinics are happy to walk you through what they're doing chairside. The protocol isn't proprietary; it's published.

There's no shame in older protocols still producing acceptable clinical results in many cases — particularly for relatively forgiving indications like generalized skin quality. But for high-precision applications — Alb-PRF for tear-trough volume, severe scar revision, advanced hair restoration — the protocol choice meaningfully changes the outcome.

References

1. L-PRF (original protocol). Choukroun J, Adda F, Schoeffler C, Vervelle A. Une opportunité en paro-implantologie : le PRF. Implantodontie. 2001;42:55–62.
2. A-PRF / Low-Speed Centrifugation Concept. Ghanaati S, Booms P, Orlowska A, Kubesch A, Lorenz J, Rutkowski J, Landes C, Sader R, Kirkpatrick C, Choukroun J. Advanced platelet-rich fibrin: a new concept for cell-based tissue engineering by means of inflammatory cells. J Oral Implantol. 2014;40(6):679–689. doi:10.1563/aaid-joi-D-14-00138
3. Standardization of RCF in PRF (RCF vs RPM). Miron RJ, Pinto NR, Quirynen M, Ghanaati S. Standardization of relative centrifugal forces in studies related to platelet-rich fibrin. J Periodontol. 2019;90(8):817–820.
4. Horizontal centrifugation introduction. Miron RJ, Chai J, Zheng S, Feng M, Sculean A, Zhang Y. A novel method for evaluating and quantifying cell types in platelet-rich fibrin and an introduction to horizontal centrifugation. J Biomed Mater Res A. 2019;107(10):2257–2271. Full text (PDF)
5. 24-protocol RCF×time grid (Solid PRF 700 g, i-PRF 200–300 g). Miron RJ, Chai J, Fujioka-Kobayashi M, Sculean A, Zhang Y. Evaluation of 24 protocols for the production of platelet-rich fibrin. BMC Oral Health. 2020;20(1):310. PMC7648315
6. C-PRF original paper (2,000 g concentrated buffy coat). Fujioka-Kobayashi M, Katagiri H, Kono M, Schaller B, Zhang Y, Sculean A, Miron RJ. Improved growth factor delivery and cellular activity using concentrated platelet-rich fibrin (C-PRF) when compared with traditional injectable (i-PRF) protocols. Clin Oral Investig. 2020;24(12):4373–4383.
7. Alb-PRF original paper. Fujioka-Kobayashi M, Schaller B, Mourão CFAB, Zhang Y, Sculean A, Miron RJ. Biological characterization of an injectable platelet-rich fibrin mixture consisting of autologous albumin gel and liquid platelet-rich fibrin (Alb-PRF). Platelets. 2021;32(1):74–81. doi:10.1080/09537104.2020.1717455
8. 2024 optimization review. Miron RJ. Optimization of platelet-rich fibrin. Periodontology 2000. 2024;94(1):79–91. Wiley link
9. 2024 i-PRF 10-year review. Miron RJ, Pikos MA, Estrin NE, et al. Ten years of injectable platelet-rich fibrin. Periodontology 2000. 2024;94(1):92–113. Wiley link

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